Windows 2000 server administrator

Since yesterday, I’m trying to log in as administrator in Window 2000 Server (Web Server) with the right password, once it started processing, it seemed that I was able to get in but after 30 second or a minute, it came back to the screen “welcome to window”. I then pressed “Ctrl, Alt, Delete” to restart the system and relog in, but the same thing happened again and again. The last determinant that I’m going to do is to reinstall the Win 2000 server. Since I don’t have any other user name to log in as a different user, I have no choice but to reinstall the whole Win 2000 Server. However, before I do that, can you suggest me any alternative? Thank you for your assistance.