BootMgr is missing.

So I get this error when I start up my friends PC (Running Vista Sp1) that I'm trying to fix.

I've tried everything, the "Startup repair" and various commands through the Command prompt. He told me that the possible cause of this issue was that he installed a "Windows 7 loader" somehow to preactivate his PC with W7 (even though it isn't possible and sounds ridiculous).

If you guys could enlighten me a little, I'd appreciate it so much.

Thanks in advance .
Boot your Vista DVD, (or download our recovery disc if you don't have one) select "repair your computer" then "startup repair".

Do this 3 times (it needs to fix several things, and can only do one at a time).

If that doesn't work, run "command prompt" from the 2nd screen instead of repair.
Use the recovery console to run a chkdsk /r against the Vista partition.
Have lunch or a nap while it runs (for quite a while) and tries to fix any disk problems.

Then try the "startup repair" sequence again.
Hi thanks for the reply, so when I try the "Startup Repair" option through the recovery disk, and i get the following error..

BFSVC: BfspCopyFile<D:Windows\boot\PCAT\bootmgr, \\?\GLOBALROOT\Device\Harddisk Volume1\bootmgr> failed! <Attempt 22 of 60> Last Error = 0x5

BFSVC: No process found using D:\Windows\boot\PCAT\ bootmgr file.

BFSVC: No process found using \\?\GLOBALROOT\Device\HarddiskVolume1\bootmgr file
That sounds like it's unable to locate the proto-boot files from the Windows folder to recreate the active files with. In which case it's the OS that's broken not just the boot.
Do you have a live Linux CD you can boot in "try without changing your PC" mode ? You can look at what's happened to the C: disk and assess what's still there, and what else is missing.
You can also rescue the user files to external storage, because it sounds like an OEM restore or factory reset is on the cards.