Ok after using my computer with no trouble for a few hours on end I decided to sleep. I wake up in the morning and have a impulse to start writing so I do. About 2 pages later my computer just shuts off. I am thinking it was a accident and I hit the power cord so I try again, and this time after about 2 minutes same thing just goes off. Then I notice the computer is hot so it dawns on me the fan is messing up. I open the case and run the computer and all is well because the cpu fan is still running, but I notice the psu one is not. I reinstalled windows to give the computer a fresh start and that did not work. Is there anything else I can try short of ordering a replacement part and installing it myself? Any suggestions would be great thanks.

P.S. I can still use the computer so the PSU is taking power, but the fan there is not moving, and this means I have to go because it is heating up I can feel it literally

A knackered fan probably isn't a software issue, which is why reinstalling Windows didn't help. Unfortunately, your only option (IMO) is to replace the part.

Before you do this, though, be aware that there are high currents and voltages operating inside the PSU. There are also charge-carrying elements (capacitors) which tend to be quite large and hence carry a lot of current. If one of these discharges through you it will hurt.

My advice is that unless you know how to replace the fan safely, just bite the bullet and buy a whole new PSU. It doesn't take much current to stop your heart, after all -- better safe than sorry.

Installing a new fan is pretty simple, as described in http://www4.tomshardware.com/howto/20030609/power_supplies-06.html . However, as t0mmyp said, it can be risky. BE CAREFUL. There is a lot of electricity stored in the psu, so if you do elect to replace the fan, be absolutely sure not to touch anything other than the fan. Insulating gloves might be a good idea, though hinder your dexterity.
Before you switch for a new one, check the connections for the old fan, maybe something just got bumped.
Unless you are uncomfortable working in the psu, I'd say try switching the fan before going to the expense of a new psu. Good luck

Thanks for the responses.

Ok I opened it and figured I could do the job myself if it was not soldered. Two problems. One it is soldered, this would not be as much of a problem because I do know something about soldering. Second the unit has circuit boards on the outside preventing the fan from being taken out. It looks like the boards are protectiong more parts (probably the ones with the high voltage like you said.). The odd part is the boards have a plastic tube going through them connecting them together and at the ends of the tube the plastic ends can screw off. Also on the first board there is a single screw holding it in place and connecting it to a piece of metal that is hanging down. The last odd part is the first board is also held on to something I can not see with two of those hard plastic twist-tie things that are usually used to keep wires from getting tangled and keep them bunched up so they look semi neat.

So in short for me to take out the fan I would have to take out a plastic tube, then unscrew a screw, that I do not know what it is attached to, and finally break the plastic ties. This would be fine except I fear a part falling and breaking the whole PSU instead of just the fan not working.

This makes me want to just get a new fan that is the exact same as the one that is not working now and simply take the old one out leaving enough wire to attach the new fan to. The only way I could see me or somone else doing this is to cut some of the casing and remove the fan, then place in the new fan and solder it in, then test it, then either replace the broken casing some way (glue?) or just leave it off.

Anyway I would like to hear some suggestions and please keep in mind I have a very low budget (about $100 right now) The replacement PSU part is $127 according to compaq. Is there some way to get one cheaper? And if I decide to get somone else to do it how much do you think it would run me?

I would still like to give this a shot myself so please give me some advice about my plan for replacing the fan by hacking the case and removing it, then placing in the new one. The soldering should be fine as long as I go wire to wire. I would cut the old fan wires out and leave enough wire connected to the bottom circuit board so I would not have to worry about connecting the new fan to the board myself and instead just solder the same colored wires together. Please tell me what you think of this and thanks again for the responses.

I would be pretty wary about replacing the fan if it requires so much work, but you can definitely get a psu for less than $127, and fans are cheap, so you might try to switch the fan, knowing that even if you break the psu, you needed a new one either way. So if you try changing the fan, good luck. :)

If you decide to get a new psu (or break the old one), you can get a good 350w psu for $51 including shipping from newegg.com (antec 350w). There are a variety of other online sellers as well, with good prices. http://www4.tomshardware.com/howto/20030609/index.html and http://www4.tomshardware.com/howto/20021021/index.html have reviews of power supplies. You definitely want to get a good quality unit, 300-350w should be plenty (unless your old one was more, but from the factory I doubt it.) So if you buy a new one, check out the reviews and shop around, there are good deals to be had.
Good luck

i buy new power supplys from ebay for 5-7 dollars each with about 5 bucks shipping, just make sure to get a good name brand where ever you buy one, but if the psu has been hot enough to shut down the pc, replace it.

What kind of supplies are you getting, kc? I couldn't find anything that I would trust for less than $40 or so. I'm in the market, so I'd be interested in where you're getting these.

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=3428186748&category=42020
this one has a bit higher shipping than i like to pay but had a buy it now of 6.99, shipping was 12.95, i work nights, so i get to watch bids all night at ebay while i am at work,...lol, i only buy new, name brand, and auction, not buy it now, they usually burn you with shipping, also check the seller's feedback rating, if it is bad or dont have much or any, just let it go, no matter how good it seems to be. i buy everything for my personal use and people who bring me thier computers from ebay, have had really good luck, when i have recieved bad items, i bought from people with warrenties so was covered. besides, i stock up when they are cheap.if you are trying to buy itmes to use in a buisness, this probably wont work well, sometimes it's hard to fu=ind exactly what you need, when you need it, i try to keep a few of everything, so i spend about $20-50 a week at ebay, but i buy motherboards processors, cases, everything except hard drives and monitors, shipping kills on monitors, hard drives are better bought from a retailer, warrenty and quality, they have alot of remanufactured they sell as new on there.

Thanks for the suggestion of e-bay I never thought to look there. Thankfully I did not have to look for a PSU unit to buy.

First I took out the fan after using a hacksaw on the case like what I described in my last post. I then took the fan to a couple of stores, but they did not carry fans that were 96mm all they had was 80mm. This discouraged me since even my local electronics shop had no fans that size and they sell used parts. I really did not want to buy a new PSU unit for the simple fact that I had already come so far (hacking the case took forever with a crappy hacksaw and improper tools). Thankfully I had a friend who has a friend who takes old computers apart and he gave me a free one =).

Thanks to all who replied to all my posts =)

You really don't want to take a chance on a cheap powersupply. Saving yourself a couple of bucks can cost you the whole computer.

The amount of elec stored in the capacitors is enough to literally melt and explode things off your motherboard. I've kept several motherboards, ram sticks etc, over the years that have been blown off the motherboard by a bad powersupply.

Get an Antec, Enlight, or one of the other good name brands. You can definitely get one for under $100, generally under $50. I would never put a powersupply from Ebay into my computer, especially if it only cost $5.

the company i work for has a stack of older computers i am supposed to destroy(dell optiplex) 486 machines, after seeing you post about exploading things off a motherboard i got curious, grabbed 3 of them, put them on the workbench and set about the evil deed. first i tried shorting out the power supply in key areas, just got magic smoke, then tried hooking 110 volts directly to the power leads on the board, more magic smoke, no explosion. threw that one away, started on the second, hooked 220 volts magic smoke came from everything, no explosion. third took it out in the plant and hooked 30,000 volts to it, it caught fire, and melted down, nothing exploded. i do see the point of buying a good power supply, some of them look like they are made of tin foil and i have seen them catch fire, but i really am curious, i want to see some of this stuff explode, yes i am bored. i have 8 more optiplex machine i want explosions, what brand of stuff exploded, cause i have intel 486 with edo ram 100w psu, all the other stuff i removed, might use it, never know.the old 400 meg hard drives were kinda fun to destroy, put them in a hydraulic press, they are thick as a dime now. i love my company thier paranoia makes my job fun at times. they want thing destroyed so nothing can be revived, i asked can i be creative, they said sure.