Switch out boards - NOTHING powers on

Alright, here's the deal ....

I took the motherboard out of my girlfriend's computer and switched it with my parent's computer's. Both are identical NF7-S's, with the exception being that my girlfriend's has Dirty_Punk's volt mods in the back of it (3 wires, done flawlessly, worked fine when I took out the board).

I put the volt-modded board into my parents computer (since they have BH5 and the girlfriend doesn't), which is in a Lian-Li case ... PC60 or something like that, I believe (dunno, didn't buy the case from the store and not real familiar with them).

Now NOTHING will power on except the motherboard itself. When I turn on the PSU switch, the mobo's green and red leds light up, but when I hit the power switch on the computer, nothing happens ... not even fans spinning.

I've reversed the plug to make sure I had the leads right, swapped it's place with the reset switch to make sure the buttons themselves weren't reversed, and checked every connection I can think of (initially, the 20-pin mobo line wasn't all the way in, but powering off then inserting it fully made no difference).

What should I do? I'm at my wit's end, and I can't think of any reason whatsoever this thing shouldn't be working when all I did was replace the motherboard with another of the same type, and the mobo itself seems to be getting power fine. I just have no clue how the circuit loops from the PSU to the power button to everything else, honestly ... and I've never actually had the fans not even start.

Any help would be extremely appreciated.

Thanks,
Dave

Hope you had permission from all involved...

On both PCs I have built (Abit motherboards) there was a little block of connectors on the motherboard for things like the power switch - maybe you should find & check those. I forgot them building my new PC and it was a doh! moment when I remembered... The details of what connects where is in the manual which you can download from Abit if you don't have it to hand.

Of course I had permission ... I bought both the computers as it is. The only thing I had to inform my family of was that if they decided to upgrade ram, not to just go out and buy whatever, because I was putting in my volt-modded mobo for them since they have better RAM than the g/f.

I already said I checked the connecting pins, as well as reversed the power and reset leads (both in position and in pos/neg arrangement within the same pin) to make sure everything there is kosher. All connections are on correctly.

Any ideas out there? I really need to have this thing done today, and I can't figure it out for the life of me. Gonna have to start ripping it apart piece by piece here in a few if I can't figure it out.

Well, it turns out that the board doesn't want to run with the 3.3v mod anymore. Tested it on a couple of PSUs just to make sure there wasn't something screwy in my main one, then took off the mod, and it worked. To be double-sure, I re-did the mod, at which point the NB fan wouldnt come on again, then took the mod back off, and everything started back up.

So, looks like the one that had the mods is going BACK into the g/f's case, and I'll be doing the mods to the parent's comp instead. Thought by just switching out boards I would save myself the trouble of doing the mods again to theirs, but ended up with twice the hassle. lol. So goes the wide world of overclocking and random mishaps.