try jumping to clear nvram. although the battery should of done this, MAYBE this will, also. A few things to do. First, find the jumper on the MBD that says either "Reset Config Data" or "Clear NVRAM". It should have a number or two. like 1,2. That means take the tiny cap and position it over what numbers it says. Boot the system. HOPEFULLY you should see something like "CMOS/BIOS/NVRAM cleared by jumper." If it does, GOOD! We're in business. Just put the jumper to its original set (probably the pins for nomral) and reboot. Should prompt you to enter bios. Check it and save settings. If this DOESN'T work, the only thing else I can say is remove the MBD from the case and set it on something anti static careful of ESD (static charge). Have the bare essentials plugged in (HDD, CPU, memory, vid card) and turn it on. I know its a pain, but this should cover everything. If you STILL get nothing the MBD is probably shot and MAYBE the CPU (doubt the memory because you've tried each individually, but could be). Go for the MBD first, its cheaper and if the CPU is shot, more than likely something got to the MBD first. If it DOES turn on outside the case you have a grounding problem. Probably the screws holding the MBD in the case are touching the etchings and the case shorting it out via ground. To fix that, just get some plastic clips to fit the screws into.