make sure under the BIOS that the hard drive is set to 'Auto Detect'
if that doesn't work, than you may have a bad memory stick. You can get a program thats bootable from a flash drive called MemTest86+ http://www.memtest.org/
(link is about 1/2 way down the page). This will test your memory upon restarting the PC if you can't boot into the OS.[/quotem
What if you can't get to the Bios menu?