Question:My computer won't boot in real or safe mode. It is not able to read either of the two hard drives. I tried the XP disc and it hung up at the "reading drives" part. How do I troubleshoot?
Answer: I would start by making sure the power and ribbon cables are securely connected to the hard drives. If both drives and not being recognized then it may be the controller where they are connected to. If they are both on the same ribbon cable, assuming they are IDE drives and not SATA drives then you may want to replace the cable, switch them to the other IDE controller on the motherboard or both.
You should also go into your BIOS and see if they are recognized there. If you cant get the computer to see them first, then Windows wont be able to see them either.
If the Windows setup does see the drive but still hangs you may have a bad drive. You may want to try only one drive at a time installed to see if one of them is bad. Just make sure you set your jumpers correctly when swapping out the drives.