Okay so here's how it's happened.
With an old 700mhz CPU, a MSI ms-6309 mobo, some 20gig HDD and about 380mb of ram, I cracked her open and installed a new video card. Oh and the "old" (old being the one before the one I'm installing) card was some 16mb piece of shit. Anyways, I install a 64mb Nvidia and hope for the best. It doesn't work (series of beeps from my motherboard), and I can't be bothered figuring out why, so I simply put in the 16mb, install the drivers from the 64mb's CD, and shut down.
I remove the 16mb once again, put in the 64mb, and it still doesn't work. So I put the 16mb in yet again, and everything's back to normal. I decide to remove the 64mb's drivers, though since they're the same manufacturer, I removed the 16mb's.
So of course the PC was sitting there with Quake and Counterstrike unplayable because of it's non-changeable 16 color 640 x 480 setting. I buy a 16mb card from eBay, and get fed up waiting.
I open her up, grab a motherboard I had lieing around, unplug EVERYTHING from the ms-6309, put in the found motherboard, and realise the case doesn't fit it. So I put the ms-6309 back in, install all the plugs and didn't even think I'd come to a problem, until *dun dun dun* front panel connectors.
After hours and hours of finding the manual for the mobo, and not having any power on the PC itself because I couldn't figure out the combination they plug in, I finally did it correctly as to what it says in the manual. Everything connected, spiffy, case nice and closed (note: the 64mb is still in there, if that makes a difference), press the power button, and nothing. Absolutely zip, nothing even goes to load.
I've no idea what to do, help if you can. Any information you need I am willing to provide.