I'm getting  a corrupt FILE error when I attempt to start Windows XP. XP will not boot up in safe mode or any other selection. When I boot up from a dos boot disk or the recover cd (in command prompt from cd) I cannot access the hard drive. The local a-drive or b-drive are the only drive specifications that will work. This is preventing me from repairing the damaged file so I can boot Windows XP from the hard drive. Any help and or suggestions would be greatly appreciated.  What happened immediately prior to this. That could be helpful.  

What kind of DOS boot disk? What file system are you using on the drive?The screen got HUNG up while COMING out of the screen SAVER. I pressed the power button to restart it and it never came up after that. Also my external modem was answering incoming phone calls, it's never done that before. I'm thinking I MAY have had a power surge but who knows.

I'm not sure what file system the wounded pc is using.

 I made the dos boot disk from my XP laptop by formatting a floppy disk with the ms-dos start-up disk option. The boot disk was fat (the only option offered).
If this is a desktop I would reset the CMOS. If nothing else, take battery out for a few minutes, then restart. At this point we don't know if it is hardware or software.

Care to offer a computer or motherboard make/model, system specs, etc., rather than we just guess?