Well it all started when I reinstalled SYSTEM on my daughter's DELL DIMENSION 5100. Everything went fine I went to plug in a USB optical mouse in back of te computer when I came back up I have a Blue Screen saying SERIOUS Hardware Failure,so I immediate turned off system . Waited a few minutes and tried to restart,nothing happened,opened up PC Green LED was light og motherboard near SATA plugins and ethernet was flashing at port.If I hit the Power Switch a dim AMBER light flashed once. I have another DELL E510 which I took the Power Supply and just hooked up the motherboard and Hard Drive but the the CDROM and system booted up looking foe CDROM and said to hit (F!) or (F2) shut down PC figured ity was a bad Power Supply. Got a DeLL5100 Replacement plugged it in Everything booted up perferctly but I forgot to hook up the USB Mouse and USB keyboard.Plugged them in but didn't recognize either,couldn't restart,so I did a Hard Shutdown.Tried to Power Up and SAME PROBLEM ! all over again DEAD PC .Someone told me to Pull the CMOS Battery out then hit the power switch and wait 2 minutes and put it back in and try to power up. Now all I get a Flashing Amber light on the Power Switch but not boot.Any Ideas on this Is my NEW Power Supply Shot or is there something wrong with the motherboard?This system is only 2 years old and out of warranty So it happened each time you connected the mouse? I see what you can't see.