I have a custom built AMD Athlon 800MHz sytstem that just had the hard drive replaced about a month ago. Occassionally when I boot my machine, my computer does not detect my hard drive. I can reboot several times and it will do the same thing. If I let it sit for awhile and come back to it, then it boots up fine but when I reboot again, it doesn't detect it. Can anyone tell me what's going on? I would really appreciate any help anyone can give me?