Fried power supply?

[Wing Nut]

Well, I had to go to my sister's place this weekend and while I was there, she asked me if I could take a look at her 2 year old Compaq.

[Wing Nut]

Further exploration has revealed a 30 gig hd, and 64 mb Ram in the thing...

[GunnerMan]

could be the PSU but as far as I know the PSUs do not have breakers and thats why we use surgeprotectors but good idea! If it has 64 megs RAM its uhh well gonna be a slow learning project...take ure PSU out of your rig and try it in there but its prolly a waste of time as im shure the whole thing is toast

[Ivan]

could be the PSU but as far as I know the PSUs do not have breakers

Most PSU's do have 2AMP breakers on the high voltage side.
These are somewhere inside the casing, and can be soldered in place if you have bad luck

use surgeprotectors but good idea!

no matter what happens, using surgeprotectors is a good idea.

take ure PSU out of your rig and try it in there but its prolly a waste of time as im shure the whole thing is toast

if the breaker fired (most likely) you can try to replace it but stay clear of the capacitors...

and at 2nd thought...
ATX PSU won't fit in an old machine, and certainly not in a compaq

[JRoc]

A bit late on the reply, but I had the same problem a few years ago, and I was on a surge protector.  

I had a cheap power supply that went haywire and sent the full charge though the mobo, frying EVERYTHING except the DVD drive. There was no visible damage to anything in the case whatsoever. The only clue was the smell of ozone when it happened, but other than that, you can't really tell until you start swapping components to see what's OK and what's not.

In short, it's very reasonable to suspect some fried parts.

[Rivers]

Is there any kind of a circuit breaker in the power supply?  

Yes there is, open the PSU and you will find a fuse inside. I bet if you replace it everything is going to work just fine.

[Ivan]

in the modern PSUs that i messed around with lately i can't find the fuse anymore...

With Compaq... be prepared for a bad surprise as some used a weird kind of PSU (Deskpro 2000 has an ATX like power switch but uses AT type mobo connectors)