Computer occasionally freezes - Why?

Every so often when I have the desktop, am in a word processing program, or in my browser Mozilla, before the screen saver starts, the mouse cursor disappears and the computer freezes for no apparent reason. Anyone have any idea what causes this? I have to hold the power button until machine shuts down and then reboot. It is annoying! Does it have something to do with the mouse.

 

Check your event logs for a problem at the same time as this occurs.

Possibly a corrupt screensaver, or the suspend feature of power options?

 

How do I check the event logs?

 

From the Run window:

eventvwr.msc

Then click each heading in the left side in turn and scroll the right side to find any errors and possible events that match your trouble occurrence.

 

Thank you.