boot manager goes missing

SUP

so a friend of mine has had a problem with his windows 7 installation since friday - after experiencing a crash, the reboot would subsequently fail to post; mostly this has happened whilst playing CSS, but has spread to simply any kind of shut down/start up.
my friend has had to reinstall windows several times now, 4 times and counting.
what error or problem that exists that could cause the boot manager to go missing?

most times after BIOS the screen would sit on black screen, on a rare occasion it has a message saying boot manager missing with no real options.

any info would be most appreciated!

Do you mean to say it's just not booting Windows, or do you literally mean the computer does not POST during boot?

I'm not sure I understand what you mean. The computer randomly restarts while he's playing CS:S?

Does Windows boot normally at all between these installs? Does it boot normally for a while and then starts missing bootloader again?

The first thought that popped into my head was some form of hardware failure (such as harddrive) but please answer Core's questions.

Is he getting any BSODs? If so, posting the minidumps could help pinpoint issues.

Sounds like to me there is a corrupt install in the boot record or the RAM may be acting up.

Has he done clean installs and wiping the hard drive clean and then resetting the partitions?

Has he tried running MemTest'86 for a few hours and seeing what results show up?

What about using the install DVD to do a repair startup? Saved me (the first time I came to the forum) on time I played with Linux...