Just bought a BFG 650 power supply. Just upgrading, no issues with my 250w one. I have a Dell optiplex 260(older i know). Once I get everything tightly secured and installed, the comp won't fire back up. Its a 20 pin on the mobo, and another 4 pin connector. Oddly enough when the 4 pin isnt hooked up, the fans fire up, but nothing else turns on. Is my comp too old for this power supply or am I just messing this up? I have yet to install my new vid card which requires 350W of power. Not sure if I need more draw from the PSU or what, but i could use some help!