NEED HELP

Ok. I installed new gfx drivers, didn't reboot and forgot about them. Then I did a system restore. This totally screwed my XP up, and I was getting blue screens. So I got my boot disk and went to repair install windows (because safe mode doesnt work). Only thing is, it gets to the point where its installing devices and freezes...nothing happens, you just reboot and the same happens again.

So. I installed a SP1 version of Windows from the boot disk on another HD, which installed fine. Therefore I know its an error on the old O/S which isn't letting me repair it. So I logged into the new XP install, and I could see all my nice files sitting there. Now I need to know how to do a few things:

[*] How do I access the protected files in (for example) My Documents via a different O/S ?

[*] How can I perform a system restore on the dead O/S by only using the new O/S ?

[*] How can I get my old O/S back?

I really really DO NOT want to reformat, there are far too many files I cannot afford to lose.

My mood isn't that great so posting useless crap which doesn't help isn't likely to do you much good. Thanks <3