I had an apparent dead CPU (AMDK6-2-350) to ensure it was in fact dead I installed it in a working system replacing the working cpu with the dead one. When I booted nothing (blank screen HD light stays on)came up. So I was sure that it was in fact a dead cpu, I then remowed the dead cpu and put the working one back in. When I rebooted the system it was still dead. Can a bad cpu kill the MB or Bios?

try reset the motherboard to detect cpu take it out turn on system without cpu for a few seconds to make it search for cpu then turn it off seat cpu correctly in slot/socket check all connection take out video card and re seat it then when you are completely done checking everything from jumpers to cables etc then check everything again i cant stress how important this step is finally turn it on let me know what happens.... do you hear any beeps or activity in the computer?