Are you still running Windows 7 Release Candidate? You might want to get that rebuilt to a full release. According to a press release from Microsoft, beginning on March 1, 2010 your system will begin shutting down every two hours. During this forced shut down any unsaved work will be lost.
On June 1, 2010 the RC version of Windows 7 will fully expire. In order to save yourself from this headache you must perform a full installation of a full release of Windows 7. As I used to say in my tech days, “F-Disk, Format, Re-install… do dah, do dah. F-Disk, Format, Re-install… all the do dah day.”
John "Mike" Wright