Boot manager is missing?

I have an HP desktop. When I turn it on it says Boot Manager is missing. I've gone to BIOS changed to boot from cd rom, I have tried to boot from Windows XP home and professional disks, it goes to Windows Setup says it is loading files but eventually it comes up with a stop code. Stop: 0x0000007B (0xF78D2524, 0XC0000034, 0x00000000) I would like to just wipe the whole drive and start over, but I can't get to a dos command to format the hard drive. Anyone have any suggestions? (This is not my computer) So I believe it has Windows 7 loaded, so I have Windows 7 on my laptop and I've tried creating a recovery disk, unfortunately my computer isn't cooperating with that. Also, when I try the windows 7 CD to boot from it just goes back to boot manager is missing hit ctrl alt delete. HELP!!!!

2010-09-10T20:08:05Z

At what screen? When I have the disk in, it goes to set up and then goes to that stop screen, where do I type in R?

Anonymous2010-09-10T20:04:21Z

STOP 7B is inaccessible boot device. I'm betting that your hard drive failed. (You can format the drive from the XP disk. Hit R at the first screen to get into the repair console, then type format C: You'll probably get an error though, because there's no more C drive.)