I was just browsing, when all of a sudden the display flickered and then aero had been disabled and my HDD went mad ... So I opened up Task manager and WinSAT.exe was the culprit, as soon as I ended the task everything went back to normal. WinSAT is the Windows Self Assessment Tool, it is used for the rating system in Windows 7 (& Vista). Dunno how it started ... I'm running Windows 7 TM. Anyone had this before ????