Yesterday, my Compaq Presario (running 32 bit Vista Home Premium) laptop stopped booting. Just a black screen. Tapping F8 to access safe mode does nothing. Just the same black screen. I can get to the BIOS, and I did initiate a HD Diagnostics test from there. It failed. And provided no repair or usable diagnostic information. I can boot using a Microsoft Vista disk, but when I use the repair option and get to the screen which should display the OS I wish to repair, it is empty. I have used multiple tools to try to correct the problems: Kaspersky Rescue Disk 10 Winternals 2005 ERD Seagate HD Diagnostics Memtest86 Ubuntu as well as the MS Vista DVD All of these products seem to be rendered totally useless if the PC fails to detect an OS. Shouldn't there some sort of process that I can run to get rid of problems on my OS, even if the computer fails to recognize that there is an OS? The SeaTools disk always displays the hard drive on the laptop, but the long test eventually tells me that it cannot repair the problems that it's found. From the command prompt (accessed using the install disk), I cannot get to my C: drive, the drive that has Windows installed on it. I get a msg "Data error (cyclic redundancy check)". Without a C: drive I can't really use fixboot or fixmbr or chkdsk /f or scannow. Startup repair (MS Vista disk) runs almost forever, finally indicating that I should restart the PC. The restart give me an error on the file \Windows\System32\Winload.exe with a status of 0xc000000f. System Restore won't work without an OS selected. I don't even think I can use my USB caddy to pull about a month's worth of pictures and documents that have not been backed up. I don't believe it's engineered to to used with the hard drive of a laptop. Am I in the position of having to reinstall Vsta on a laptop that was working perfectly a few days ago?