When it comes to hardware, most things can't be fixed.  I remember disassembling a CD-ROM back in the old days and fixing some tiny spring that had broken, but that's when they were expensive and valuable.  Today, I'd just buy a box of Cracker Jacks and hope a new drive was the free prize inside.The good news, at least compared to software issues, is that hardware problems are relatively easy to troubleshoot.  Each type of failure usually has its signature benchmark.

A quick overview:

• Memory chips failing usually cause "out of the blue" errors, like when trying to save a file.  An error box will usually pop up, and there'll usually be some real long numbers in it (probably indicating what memory registers are having the prob).  Unless it's a massive chip failure (rare), the machine will usually run fine otherwise.
   
• CPUs overheating usually cause the computer to suddenly reboot.  I've almost never heard of a CPU chip actually going bad.  It's usually an overheating issue because the cooling fan has slowed down over time and a heavy dust coat is making everything run hotter.
   
• Hard drive failures mean the system won't even boot.
   
• Motherboards are somewhat prone to failure, just because so many parts are involved.  They're actually divided into individual areas (hard drive bus, memory management, BIOS chip, audio and video circuitry, etc), but all it takes is for one tiny resister to blow its cookies and that's it for boot-up.
   
• Power supplies are also prone to failure, simply because they run fairly hot.  If it fails, though, it'll be pretty obvious.
   

Error Beeps

When the computer is first turned on, it goes through a self-check, making sure the various pieces are there before continuing.  It needs a keyboard, memory, CPU, monitor, and a few other things.  Note that it's not looking for peripheral devices like speakers, mice, ROM drives; and it's not even looking for a hard drive because you could be booting up from something else, so a hard drive isn't deemed 'necessary'.

If it finds something amiss, you'll hear a little series of beeps coming out of the bottom of the case, not your speaker system.  There are a whole bunch of error codes, but the three usual culprits are a loose or bad memory chip, a loose or bad video card, or a loose monitor or keyboard cable on the back of the case.
 

1 short beep	Normal POST – system okay
2 short beeps	POST Error – error code on screen
No beep	Power supply or motherboard
Continuous beep	Power, motherboard, keyboard
Repeating short	Power, motherboard
1 long, 1 short	Motherboard
1 long, 2 short	Display adapter problem
1 long, 3 short	Enhanced Graphics Adapter
3 long	Keyboard

 

 

 

 

 

 
 

Memory Chips

These are easy to both test and replace.  Assuming you have a DVD burner, download this mem-tester and burn a disc with it.  Reboot and it'll check the chip(s).  It'll take quite a while, just so you're forewarned.

If one's bad, just press down on the little clips on either end and they'll pop right out.  Just be sure to get the alignment slot on the bottom in the correct position when pressing in a new one.  Keep pushing until both end clips slip back into place.
 

Motherboard

If the system is getting power, you can hear the hard drive spin up, but you're not seeing anything on the monitor, it's possible your motherboard has blown its cookies.  There are a few things you can check:

• Are all of the fans running? There should be one over the big CPU, possibly one somewhere else in the case, and one inside the power supply blowing out the back of the case.  If the one for the CPU isn't working, it's possible you cooked the chip.
   
• Go ahead and press down on every chip you can see, making sure it's seated on the motherboard.  This isn't a problem with newer computers, but the chips occasionally rode out of their sockets on older models.  Do the same to the vertical memory chips and every plug you see.  If you have an PCI cards, give them a big push.
   
• Got a battery tester? There's a small 'watch' battery on the motherboard somewhere, keeping the BIOS information intact even though the machine's unplugged.  Find it, press on the little clip with a small screwdriver or something and pop it out.  Test it if you can, otherwise hoof it over to the hardware store and let them test it.  Replace if necessary.

Note: If you remove the battery (even to test), you'll have to remember to reset your system clock after you boot back up.  And it's best to reset it via the BIOS, itself.

It could also be that the hard drive is spinning up but the circuitry is fried, so the next step would be to either test the drive on a different system, or, better, put in an old system drive you got stashed in a drawer somewhere.

And none is this to discount the small, stupid things, like the power switch going bad or one of those tiny wires pulling off its pin and getting lost in the clutter of wires.  Grab a bright flashlight, your most powerful reading glasses, and give everything a real close look.

If everything else seems to test out and it's probable the mobo has fried itself, lucky you gets to decide if it's worth bringing it to the ($$) repair shop or just buying a new tower.  If you could get a shop to do a free or inexpensive estimate, that'd be the way to go, since it could still be something simple.  If the techie says the whole thing's cooked and needs to be replaced, at that point it'd probably be better just to buy a new tower.
 

Hard Drives

The usual symptom of a failed hard drive is turning on the power in the morning and nothing happening.  Sometimes they still spin, sometimes not.  In theory, after all these years of hard drive upgrades, you should have an old drive stuffed in a drawer somewhere.  Ideally, it should be an old boot drive.  Swap it with the current drive and see what happens.

If it's just a storage drive, then you'd (ideally) copy one of your image files to it and let 'er go.  Otherwise, slap in a Windows install disc and do the dirty deed.  If everything works fine from the old drive, your present drive is history.
 

ROM Drives

It's not uncommon for a CD or DVD burner to stop burning, but still read discs.  This is assuming it stops burning discs while you're in the middle of a stack of blanks, not trying out a new brand.  Not all brands work with all burners.

It's a long shot, but the one thing you can try is a commercial ROM drive cleaning disc.  It has a couple of small brushes on it that clean off the laser lens.  I've never had one fix a problem but it's the one thing you can try.

If that doesn't work, you're off to Best Buy or Office Depot for a replacement.  If you're in a city and have a choice of stores, check the newspaper ads or store flyers for bargains.  Note that any sales on the web site are usually not reflected in the stores and vice versa.

There's one important step you need to do before you replace it.  Pop the side of the tower off (or top of the case) and remove the bad ROM drive.  To remove the front panel on most towers, just look at it closely.  It'll either be a few obvious screws from behind or some press-in plastic clips.

On the back of the ROM drive you should see a little 'jumper block':

Look on the top of the unit and somewhere will be a little diagram describing what each jumper block position means.  It'll usually be 'Master', 'Slave' and 'Cable Select'.  Look at the jumper block and determine which position the unit is in.

Now look at the new drive and move the jumper block, if need be, to make it the same 'Master', 'Slave' or 'Cable Select' position as the original drive.  Don't just blindly put it in the same position; check the diagram.

Slap it in the case and you should be good to go.
 

Keyboard

One of the few peripheral devices you have any chance of repairing is the keyboard.  The obvious case would be a key starting to get a little iffy, then giving out altogether.  That means a tiny piece of grit has gotten in between the two thin sheets of plastic underneath the key, block the contact strips from touching each other.  You could always try tilting the keyboard sideways and bonking it, but if that stirs up even more crap and you end up with seven malfunctioning keys, don't blame me.

Proper procedure would be to take it apart and clean it, then carefully reassemble it.  Turn it over, remove all of the small screws, turn it right-side up and slowly pry it apart, watching to see what falls out of where.

If you want to give the whole thing a good cleaning, pop off all the keys.  Use a couple of butter knives or small screwdrivers to pop off the ones you can't get your fingers on and make sure you pop them straight off, not at an angle.  Then dump all the plastic parts in the sink, blast them with 409, let them sit for 20 minutes, then rinse them off.  Blow out the droplets from inside the keys with your mouth or an air can so they'll dry well.

Clean the clear flimsy 'contact' pieces of plastic that sit under the keyboard carefully with some paper towels and Windex.  If the contact point where the cable connects to the keyboard is a strip of copper, take a clean pencil eraser or copper cleaner like Brasso and clean everything up.  Reassemble the whole mess and pop the keys back on.

Note: The space bar can be kind of a bitch to get off.  Use a small screwdriver to pry the wire 'catch' off the hook, if that's the type you have.  Try not to actually break anything.  It pops back on easily enough.
 

Power Supply

If you hit the power switch and nothing happens, you'd better hope it's the power supply.  They're cheap and easy to replace.  Because if it's not the power supply, it'll be an item that is decidedly not cheap and easy to replace.

The basic test of the power supply is whether or not you can hear the hard drive spin up when you turn the power on.  If it does, but nothing else is happening, that could be a number of things as mentioned up above in the 'Motherboard' section.  If the whole system's dead, then you start with the power supply (because it's easy and cheap) and hope for the best.

Also, if you have a network jack (and most machines do), you'll normally see a small green light on the back of the tower.  This light stays on even when the power switch is off, so if the light is off, you're almost guaranteed it's the power supply.  If the light is on, but nothing else works, then the power supply is probably okay and it's either something in the power switch routine (like one of the tiny wires got pulled off) or the motherboard.

First, unplug everything.  There's usually a retaining clip on the jack connecting it to the motherboard.  Sometimes there are two jacks.  Yank off the power cables from the ROM drive and hard drive, undo a few screws on the back and that's it.

Head over to Best Buy or similar.  Get one with the same wattage or higher.  Yank the one at the store out of the box and carefully compare the ends of the cables and screw holes to yours.  Installation is a snap.

If you then hit the power switch and it's still dead in the water, you might have serious issues.  Some of it you could troubleshoot yourself, like by swapping some of the components, but only a shop can test things like the motherboard.

Actually, if you'll look at a motherboard objectively, it's a pretty simple thing to replace, assuming you're replacing it with an identical board.  You carefully scribble down the wire colors and where they go, then the board is usually held down by a screw or two and some plastic 'stand-offs' that keep it away from the metal case.  Pop it out, pop the new one in, carefully hook up all the wires as per your exquisitely clear diagram and you should be ready to roll.

The hitch comes when you decide that, well, as long as you're spending the money on a new mobo, you might as well upgrade your CPU as well… but now you're not just replacing the mobo in a quick, snappy manner, you're adapting it to the case.  And you just know something's going to go astray at some point.  So, yes, if your steely resolve can keep you on the straight and narrow and you merely replace the bad mobo with the exact same model, I can semi-guarantee you that the process will be fairly quick and painless.  If you upgrade or buy a different brand, well, keep the receipt.