Im helping a friend out trying to fix his computer. The problem was that the computer was freezing and just hanging. It was so unresponsive that sometimes it wouldn't let me access the start up options. We did a factory restore and the computer still froze. My friend decided that he would get a new hard drive and he did. The problem now is that sometime in the bios it won't read the hard drives after a while and it does when I take the cmos battery out for a couple minutes. What can be the root of the problem?