Ok I tried upgrading my os to vista then decided I wasn't going to but ever since then I have been having problems with windows xp. When I boot up, I am given an option of choosing windows xp, or windows xp setup. I then have 3 situations:
1. If I choose windows xp my computer runs normally.
2. If I choose xp setup nothing happens I get a blank black screen.
3. If I do nothing I get a black screen that has one message, at the top it says windows is missing <windows root>\system32\hal.dll
How can I set my computer back to its normal state?