None at all since you didn't supply what's in the EVENT VIEWER which should contain a record. Also, you didn't detail all about your use of antivirus, firewall, anti-parasite tools since soon never used such software because no-one told them to.
A rather safe "fixes many things" is to use IEFIX which you can find with google.com
Until more is told, not much can be offered.
Since SP2, Windows XP Pro won't start in any of the Safe Mode choices. It delivers an error message that "Windows did not start successfully." It then restarts, and will restart in Normal Mode.
Does anyone have a clue as to what may be wrong?