I really need help

It happens when i am using lw and the screensaver comes in, when i go back to use the computer the entire system crashes!!!
i tried to uninstall the program and reinstall it agan and it will still do it . When the computer crashes and i send for a report at microsoft it tells me the problem was caused by a driver, software or hardware.

The only way to stop this is to turn off the screensaver

If anyone knows what to do, please reply