Unfortunately, you've given us no information about the computer or the problem you're seeing.. Make and model? Laptop or desktop? Operating system installed? If the "screen is blank", does that mean there's no power to the machine, or is the problem just with YOUR "admin account"? Do other accounts work OK ?

Most cautious folks create two admin accounts, just in case one goes bad.. Is there another admin account on the machine you can use? Have you tried using the hidden "administrator" account which is available in "Safe Mode" on Windows XP and must be enabled to be usable on Windows 7, etc.?

Hope this helps and let us know more.