I was wondering if it was safe to cut an un used AUX cable and possibly one or two un used power cables from the power supply. They are unnessesary because the power supply was mean't for a larger case. Will cutting these cables screw anything up? Can I just cut them and stick some electrical tape around them? Would appreciate any advice.

Yes, you can. It is just a standard 12v DC power source. As long as you insulate the electiical potential from any ground, it will be safe. I would not do so unless you intend to neve use the extra power leads though. The only stupid question is the one that is not asked.

hey, Why don't you just get some electrical ties and tie them up. U may one day regreat cutting them off!

Personally I'd remove the old-style AT connector cable which is still included with many PCs but I'd keep the drive connectors tied up with cable ties. I know you can use cable splitters if you decide o add hardware in the future, but it's not always a good idea to put too many things on same cable.

I'm with Mercho on this. My PSU has two bunches, and I only use one. The other is fastened out the way to one of the side rails with a cable tie. Why invite potential problems by cutting anything?

"Can I just cut them and stick some electrical tape around them?" I'd put a bead of silicone glue on the end of them instead of tape. You can pull if off later if you want and it looks better and seals better than tape.