User account start up, strange dialogue box, can log on to XP

[Liquidshadow]

When my computer starts, there is a dialogue box that comes up on the
user account log in screen. There is no words other than two buttons
(yes and no) and a red X on the top. Hitting either of these buttons
logs me in and immediately logs me out. Since I can't get into
Windows, I can't figure out what is going on. I am assuming this is a
virus, but i can't run my virus detection b/c i can't get into
windows. Does anybody have any idea what this is and what i can do
about it?

Thanks in advance
liquidshadow

 

[Malke]

When my computer starts, there is a dialogue box that comes up on the
user account log in screen. There is no words other than two buttons
(yes and no) and a red X on the top. Hitting either of these buttons
logs me in and immediately logs me out. Since I can't get into
Windows, I can't figure out what is going on. I am assuming this is a
virus, but i can't run my virus detection b/c i can't get into
windows. Does anybody have any idea what this is and what i can do
about it?

Thanks in advance
liquidshadow

Can you get into Safe Mode and run your antivirus program there?

Malke