I remember some time ago I witnessed a fellow use a certain program that was usb-booted. It allowed you to go into your HDD, bypassing the Windows login, and extract files.
If I remember correctly it was Linux based, but was able to copy files from the W7 file system. Basically it was a way to get around a corrupted boot or a virus-riddled HDD, get the files, isolate them and virus scan them.
If anyone knows what this program (or others like it) are called, I'd be much appreciated.
Posts
http://www.hiren.info/pages/bootcd
Download: http://www.hirensbootcd.org/download/
you can use it to run a combofix scan. It also has copy options you are looking for.