PC will not allow log on after cleaning

After cleaning a PC at the office today, my computer reboots, but when clicking on a user, admin or other, the system says logging on, then immediately saving settings and returns to the log in screen.

Will not work in safe mode or with the most recent config settings if hitting f8 when rebooting either.

I cannot log on at all.

HELP!!!

 

2 questions (at least for now) that will need to be answered. 1) What operating system? 2) When you say "cleaning", just what do you mean? You ran a program? If so, what program?

 

Operating system is XP Professional. By cleaned, I mean I ran Ewido Anti-Spyware and found 89 problems. Performed suggested solutions and rebooted.

Thanks for the response.