A couple days ago i tried replacing my cheap 512MBx2 ram with 1GBx2 of new DDR 400 A-Data brand ram in my ECS socket 754 -755A2 motherboard. All had been working fine with the previous setup, i just needed more ram. When i plugged in the ram it was quite a bit taller than the previous sticks and actually touched the large heaksink over my AMD 3000 64bit processor. I didnt think much of that at the time, but when i was finished replacing the old ram and plugging the new ram in i suppose the ram was still touching the sides of the heatsink park of my zalman brand fan. Anyway, i powered it up and instantly the smell of buring electronics came out. My moniter did not power on, it just remained on standby, and my PSU fan stopped spinning.
I unplugged all of the unnecessary parts to see if anything would apear on the moniter but neither of my AGP graphics cards tested worked. The hard drives still spin up, however like i said the PSU fan is broken so i cant imagine the PSU will last much longer. I think the PSU makes a loud noise when its on now in fact so i havent touched that PC in a couple days.

so to recap:
Moniter: Works fine... just not when connected to the broken PC
Graphics card: fan still spins at least, may still work
PSU: fan doesnt spin, but still provides *some* power. loud beeping when turned on now
Processor: no idea if it works
Processor fan: Still works fine
Motherboard: who knows whats wrong with it
HDD: seems to be fine, at least it sounds fine, cant test it though

Geforce 6800GT, AMD 3000 XP 64bit, ECS 755A2 (form factor 754),
Seagate 80GB HDD, 500 or 550 watt power supply (not a cheap one either just cant remember the brand), 2GB Adata brand DDR 400 ram

motherboard specs-
ECS Web Site

WTF did i do to my computer!!!

I would say that you have major failure(s)
A short could have been created ... which fried the mobo/PSU/CPU.
A "burning smell" is never good.
You can try salvaging what you can.

I am sorry.

I would start by replacing the PSU and trying again. Try it with the old RAM first. I would wager the new RAM is busted now. Hopefully your other components are in the clear.