I'm new here and just registered to ask this question because I seem to have a major headache over this. I just replaced my old computer's case (Gateway SX2800 Micro-ATX) with another that supports my motherboard, and the difference is that the case is bigger and I can now install a PCI Express graphics card. I bought a new power supply that will fit in the new case (350W) and connected everything correctly. However after finishing the replacement, I got this error while the boot which displays text reading "CMOS Checksum Bad." I know what the problem was which is a CMOS Battery issue. This error never happened before by the way. I decided to make sure that it was a one time thing by powering off the PSU on and off, but the error still remains. So I tried resetting the battery by removing it for 3 minutes and then replacing it. After taking the battery out, the computer wouldn't power on at all. When I say power on I mean the switch doesn't glow, the fans don't move, nothing... Please help, I really need my computer to operate again.