put hdd in your pc .. wipe it format it ... use one of the s.m.a.r.t. disc monitors to look at any errors the hard drive has ...
if it has errors .. bin it ... if not reset jumpers to master boot from dvd and install windows ... if it fails again run memtest booted from cd to check memory...
bios can be updated in most mobo's by using a setting on bootup to look in the pc for an update file .. check mobo site for details..

personally i suspect memory tbh ...