Computer was working perfectly fine.  Blue screen and not it won't boot at all.  Gives AO code on the motherboard and on the monitor in the bottom corner, but will not boot.  When we tried to repair or reinstall windows, it does not see our hard drives at all.  All settings in the BIOS match our other computer (identical setup), so we aren't sure why it won't boot. . . .   This is the second time it has done this to us, but the first time the bios settings had changed. . . this time they have not. 

So crazy, all this stuff is brand new, not even a few months old.  I have the identical system as my husband and his hardrive won't load my system either.  Same code, So I do think it's the hard drive.  But his system isn't seeing his other hard drive either. . .   I will try what you just said and see what happens. 

Sounds like you guys need to buy some new drives for testing.

should of got PNY man...telling ya seen some of that Toshiba stuff seemed like can go through some hell and back. A fluke, Samsung has been highly regarded usually with the drives...but I did admitting try to avoid some of the Samsung dram...they've had some stuff die apparently, my understanding.