If your Alienware-OEM 460w PS is modular, the easiest way would be to order the Alienware-OEM 850w PS from Dell Parts.
N1WJD - 850w Power Supply (Delta-made model)
There is one connection that would need an adapter cable. The Optical Drive uses 15 pin to 6 pin mini sata power.
You can then use a SPECIFIC EVGA power supply.
EVGA SuperNOVA 750 B1 110-B1-0750-VR
The B2 BQ G2 models DO NOT WORK. The power supply is more than a single rail of 12v and a single spec of WATTS.
So, I installed the new parts but the computer won't turn on now. Everything is plugged in so I don't know the problem. Please help!
What parts did you install?