Motherboard ATX power connection problem? new mobo no go?

You can use a 20pin connector with a 24pin mobo, but you should probably use an adapter. They're pretty cheap, and you can get 'em on Newegg, FrozenCPU, Performance-PCs, ect.

If nothing is turning on the psu is probably at fault. Hook a few case fans up to it and short a green and black wire on the 20pin connector.

Like this:



If the psu doesnt turn on it's most likely dead.

UPDATE.

Ok, its all working now.

I took it out of the case and on a cardboard box, taking everything off, redid the cpu and heat sink, got it to boot once, but then it wouldnt.

Took every off again, redid the cpu heatsink, tested and got a beep. I then added one thing at a time, each time testing for a post beep. This was my process

1. clean cpu, resinstall add thermal paste.
2. Put on heatsink and attach fan but dont screw on and test with hand pressure. Got a beep
3. attach heatsink and fan, beep
4. One stick of memory, beep
5 2nd stick of memroy, beep
6. video card, beep
7, hard drive, beep
8. Add various case fans (mostly just to make sure it wasnt the psu crapping) beep
9 DVD/cd RW, beep
10. Floppy. beep

Take it all off again except heatsink and memory, install into case with out screwing it in. got my beep, screwed it in, got my beep.

And then I repeated the above process from 6 down.

Now we are all good, after many hours of fiddling.

Thanks all