if you hit the space bar on the keyboard first? Moving the mouse is a way to wake up the computer out of hibernation. Tapping the keyboard (any key) also can be set to do this. Seems it is not coming out of hibernation correctly or not going to sleep correctly. Lots of possibilities. I would disable hybernation or make sure all the settings are correct for hybernation. Did this work before? Someone been in the BIOS recently or added a new mouse or other hardware, changed the boot oreder etc?
After hibernating for a while, my computer is shutting down as soon as I touch the mouse. Occasionally when I reboot, the screen is frozen. The green power light stays on but fizzles away the moment the mouse is moved. Grr. Any help would be greatly appreciated.