History or snap shots

I am having trouble with a user on my computer that keeps deleting all of the history and lying about where they are browsing and uploading onto the computer but later deleting.
Is there a program that I can run in the background that they will not be aware of so I am able to view the pages/ sites visited in a format that doesn't require me to enter passwords to view pages ie a snapshot. I am not sure if this is even possible but I was told if anyone could help here would be the place to find it!!!!!
I have windows vista and am running windows 7.
Any tech help and or advice would be muchly appreciated!!!

 

You could have a look at Google Desktop. That can be set to record browsing history and I think you could look at where the person has been afterwards. Not sure if you can have it on without an icon in the system tray though. Maybe it would go unnoticed for long enough.