Some users have begun to experience sudden unexpected shutdowns, generally after the computer is idle for some time, after installing Windows 7 RC1. These shutdowns occur most often when the power usage setting is set to default (balanced).
Uninstall hardware drivers In some cases, this issue appears to be caused by installation of incompatible hardware drivers. Try uninstalling any recently installed third-party drivers then restarting. To do this, click the Start button then navigate to Control Panel > System and Security > Device Manager. Right-click any recently installed third-party items and select “Uninstall” then restart.
Turn off hybrid sleep You may also want to try going to Power > Advanced > Sleep and turning off “Allow hybrid sleep.”
If you are experiencing a similar issue or know of a solution, please let us know.