If you want to know who was using your PC when you were inthe room. Go to START and then RUN Here you type " eventvwr.msc " Events are stored in three log files. 1. Application 2. Security 3. System These logs can be reviewed and archived. But this time i need " System Log" in the left hand column in the list of events. Here you can see the date and time when you were not at home and your PC should have been off. Double click on the eg:info n it will show you the detail. 2nd Purpose: You can also use this log to see how long someone was on the PC. Just look at the time the PC was turned ON and turned OFF on that day!