F12 XFCE hanging

Hi All, I installed F12 XFCE this morning using the USB boot.The system had hung twice since then. The mouse pointer keeps rolling around the screen but no click is possible and also the keyboard goes out.. Finally i have to hard reboot the system to recover. Please help me out of this. I don't know what needs to be provided along with this report, but I'm open to discussion.I can provide the the system details if needed. Thanks Saurabh