Er, if all you need to do is replace the white connectors, that's easy enough. Go to your local Radio Shack equivalent, get the right replacement connector, and you'll see that the pins (or socket-linings) simply crimp onto stripped leads and pop into the housing. Shouldn't be more than US$5 for a few. (Some people consider these part of the "Molex" family of connectors, I'm not sure if that's accurate, but if you say "like a hard drive power connector" they'll know what you're on about.)
If the wires are coming loose pins-and-all, you might be able to fix the barbs, but chances are they've snapped off and are rattling dangerously conductive 'round the bottom of your case.
Or if you don't have a good electronics store around, buy a "Y" drive power cable from any computer shop, lop an end off, and solder or butt-connect the leads together by color. (In the US, you can now get a ridiculous array of can't-be-bothered-to-solder wire-joining-devices in the automotive section of any big chain store... or use a pair of automotive IDC connectors if you can't find better.)
