I've worked brief stints in 'IT Support' for local companies before. If it's a Dell, it's usually rebranded standard aftermarket stuff rearranged to confuse. (The lite-ON PSU is a dead giveaway.) If searching the other forums or using pin 13 really don't work, you can try using a DMM to measure one of the wires to ground. One of the wires should read a voltage (usually 5v) and at the same time magically jump-start the PSU. It's usually the green or the brown one if I could remember correctly.
EDIT: Server PSUs are designed for high load requirements. You need quite a high load to maintain stability.