User Switching Problem ?

Hey guys, i have a really annoying problem and i hope you guys can really give me some fix for it.

I have windows xp and when i try to switch users Usually when i need to open a differnt program on new user. I try to and i click switch users it takes me to the user select screen and i click on the other user. It flashs and takes me right back to the user select screen. IT WONT LET ME SWITCH

I cant figure it out i tried it with NO programs runnin at all and it still wont work any help would be HUGE. Thanks !

 

Hmm i cant find a topic on this ANYWHERE