winlogon.exe has stoped working

Hello guys and girls,

I couldnt find any proper anser or solution to my problem.

Now, I got a MBP 13" early 2011 and works just fine, now the thing is that (AS SOON AS I GOT IT) I installed windows 7 following all the bootcamp steps and it works perfect except for that when windows starts I get this error " Winlogon.exe has stopped working. What is that? How to fix it? Some people says its a virus, but I didnt even connected to the internet or loaded any file before using the notebook. And the windows copy is an original one. How come?

Any toughts or help I could get? Thanks a lot!

Mariano