I'm helping one of my friends work on his computer. It is a Dell Dimension 4500 desktop, about 2 years old.

Here is the problem:

A few weeks ago the power supply started making a weird noise. Like the fan was going out. So we took it out of the computer, disconnected all the power leads from the mobo and all accessories, and plugged it in to try to find the source of the noise. Dumb move, it shocked the fuck out of me and sparked. So, it was fried. We put it back in, and nothing. No green light on the mobo, and the computer wouldn't start. So, i looked around and found a brand new power supply with the exact same part number on Ebay. It came in today, and we tried to install it.

After installing it and hooking everything up, the green light on the mobo turns on. When the soft power switch on the front of the case is pressed, the green light behind it turns on, but nothing else happens. The computer dosen't boot, and no fans come on. No power supply fan, no case fans, or anything.

I called Dell tech support, and they seemed to think the mobo was bad, which i highly doubt, being that 1. the guy could barley speak english 2. it worked perfectly before and 3. when the power supply was fried it wasn't hooked up to the computer in any way shape or form.

The power supply from Ebay appears to be brand new as listed....the seller had excellent feedback, and it is dust free inside and out. I'm thinking it might be fried, so i opened it up. No charred circiuts or connections.

I'm thinking the problem might be in the power switch somewhere. For some strange reason the wire from the soft switch goes in through the sound card.

I would try the PSU out of my computer, but i've heard that Dell PSU's and mobos aren't compataible with other products. Otherwise i would try it.

So....any ideas?

Shocking as it may seem, Dell tech support may be right on this one. Dimension motherboards tend to be a finicky lot. When you plugged the original power supply back in, something may have been just enough out of spec that it killed the thing.

Read the chronicle of me and my parents' system here if you need an example. If you wantmore proof, just read through the online forums Dell has for more motherboard horror stories.

Dell's are horribly finicky about anything you do to them. When I was on co-op the IT department was upgrading the memory and graphics card in my Dell workstation and the Dell didn't like something and fried the mobo for no apparent reason. Took 3 days for Dell tech to come and fix it.

I've had nothing but bad experiences with DELL. 5 Mothorborads, 2 modems, PSU, set of RDRAM, a HDD, complete set of IDE cables, Zip250, DVD-Rom, and Keyboard. Elapsed time about 20 months.

Well.....after talking to more people it looks like the mobo might be fried. All i need to do is find out of i can use a regular ATX power supply on this computer. It has the large 30-pin (roughly) connector and a single 4-pin connector on the motherboard. Same as the connectors from the computer i just built. But i'd rather not fry the mobo if it already isn't. Anyone know how to find out of certian Dell's can use a standard power supply? If it can, i can easily see if the mobo is bad or not.

You mean 20 pin? I would not try a different power supply, since on some earlier models Dell made the mobos and the PSUs to only work with each other. If you plug in a different PSU, you may ruin both the PSU and mobo. Look it up online though, I'm not sure if the 4500 was one of those proprietary models.

How do they fix fried motherboards? replace them? go to radio shack and replace resisters and chips (Sadly I tried this once... it actually semi worked).

Well, another power supply was tested on the computer. It worked. Strangley, the mobo isn't fried. Thanks for the help.

Actually, if a capacitor blows, then you might be able to repair it yourself if you can use a soldiering iron. I would just hope that it didn't fry anything else when they blew...