If the machine can't be booted, even into SAFE Mode, what do you suppose the folks over at Malware Removal would do to get a HJT Log or use any other advanced tool?
I think until you resolve the boot issue, we're all in the same situation.
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Thinking first of safeguarding the data, consider removing the Hard Drive, installing into a second machine as "Slave", then copy/paste whatever important data your friend wants to preserve.
Alternatively, you could use a pre-windows environment CD, like BART CD, to boot a minimal operating system from CD-ROM.
Take a look at the ultimatebootdisk, here:
http://www.ultimatebootcd.com/
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You may be able to effect repairs from a bootdisk environment, or at least harmlessly get a better picture of the situation.
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Once you have the data preserved off-machine, you may be able to utilize Recovery Console to effect a Repair Installation, or if necessary, a format and reinstall.
In most cases, a Repair Installation can be completed without hazard to saved data, settings, drivers, and updates.
HOWEVER, best practice would backup any important data before attempting procedures from Recovery Console.
Keep us posted with your progress.
—–oh, yeah. If you are able to get the machine to bootable condition, post a HJT Log over in Malware Removal.
No sense optimizing the system files, only to have some malware junk corrupt them again.
Best Regards