XP logging off after logon

Hi

I have windows xp when I logon it is automatically logging off. The sequence is as follows:

- loading your personal settings
- saving your personal settings

and it logs off

I have tried running on safe moded but it didn't work. Please someone help me as I have important data on that hard drive?

2 questions:

1. did you have ad-aware installed on your computer before this issue?
2. do you still have the windows xp install discs?