Old timer

Throwing it out there to see if anyone else has this problem and if they have fixed it. Every so often I get a flash of the log in screen for 1/2 a second while in game play.Runnig on windows 7 intel 3 a Nvedia 1g video card macafe antivirus. Hoping I have a wrong setting. I upgraded the driver like I was told by support did not help.It's not happening on my old pent 4 xp 256 video card computer. Would apreacte any help I can get.