OK, so I decided to put together a computer, but I'm having some trouble. Hopefully it's of the "you forgot something obvious" variety, rather than "it's broken". The thread is titled as it is because I imagine that if I fix this problem, others will come up I'll also need help with. So I installed the motherboard (Asus M3A78 Pro), chip+HS/fan (Phenom II X4 920), power supply, case fan, SATA hard drive, and DVD burner, and plug everything together (including the case audio/USB/power switch cables). The only thing that was confusing was the case fan, which has a second plug in addition to the CHA_FAN1; after hunting around for a while I decided it only needed the other if I was using a legacy motherboard without a CHA_FAN1. I plugged the computer in and was rewarded with the motherboard light. Next I turned on the power and saw both the processor and chassis fan spin up; good so far. Unfortunately, I didn't get anything on the screen -- not the POST, not BIOS, nothing. What now?