I know I blogged about tech support resources a couple of weeks ago but it's worth another mention - especially as I am now a household deity for fixing daughter's PC this past weekend, in the midst of her GCSE revision.
For some reason she was only able to log on with a temporary profile and then lost whatever documents she had been working on when she logged off. She was also unable to navigate to any of her documents / photos etc, and had to search for them individually.
A quick search on community forums brought up the possibility of a corrupted user profile, with instructions for creating a new one and copying across files (minus corrupt ones).
All is now well and I have achieved god-like status (for a day or so anyway) and revision-crisis has been averted (til thursday's Chemistry exam at least). So if you get stuck, it really is worth trying the below resources for help.
Microsoft Answers (US) community forums - ask a question, find answers
Microsoft Fix It - automated solutions