P4 rig wont turn on unless...

[gman343]

Hey everyone, got a bit of a problem. I have an old rig with a 3.4ghz P4 on a Asus P4C800E mobo. A few weeks ago I moved it into a different case, and all of a sudden it wouldn't turn on. The mobo would give a green light internally, but everything else would turn on for less than a second then turn off.
I removed one stick of RAM and all of a sudden the system would boot normally. My question is this: what is most likely to be the real problem here? Is it most likely just that the RAM has gone bad and needs to be replaced, or could there be something else?
I'm asking because I've never seen this before and I don't want to go spending money on this dinosaur trying to guess which part to replace. Really appreciate any help/opinions on this!

 

[Noobie101]

I would assume the same thing and replace the ram. But let the experts tell you. I would like to know also.

 

[gman343]

Ok, weird development with this...

The system boots normally with one stick of ram. Last night, I tried with both sticks last night and all of a sudden it would boot. I installed Windows XP once it had booted normally, but during the installation a burning smell started coming from the PSU. A very strong burning smell at that.

So, I'm guessing it's time to replace that PSU.