I bought a used t4215, but it seems to have locked up after I tried to upgrade the harddrive. I put the old harddrive back and the computer still won't start. --it is not a harddrive issue, both harddrives worked fine prior to installation and work well in an external 2.5 sata enclosure, and the comp still has the no boot problems with everything unplugged (including harddrive and batteries) other than the power-- The computer can power on and the status indicator shows numlock, capslock, and scrolllock symbols all blinking. I looked up the error code and it means that there is an error before the BIOS POST and the BIOS codes aren't even being read. Any ideas what could be wrong? Would replacing the motherboard allow it to boot?

It's either the motherboard or the processor. You could try flashing the BIOS from a floppy, but I'm not sure you'll even be able to do that as it doesn't sound like your computer boots far enough. Getting a replacement motherboard will most likely fix it, but there is the slight possibility that the CPU is bad. PS: Try resetting the BIOS to defaults using the jumper on the motherboard. Also check your power supply. -Ryan Adams Free Computer Tips and more:http://RyanTAdams.com Paid Tech Support: Black Diamond

Thanks, I tried disconnecting the CMOS battery to reset the bios but it doesn't seem to have changed anything. Does it need to be taken our for a certain amount of time?