blank screen

when i start crossfire everything loads up but when the log-in screen is meant to come up it doesn't it just stays black and it doesn't even have the not responding mark on the top it wont go off that untill i restart my computer manually

pc specs

windows vista
directx 11
Nvida geforce 9500GT
2.3 GHz


please help i really really like this game and i haven't played it for atleast 5-6 months now