|Can't help but wonder why you want to do this.|
There are EventMonitoring options out there. Google has lots of hits.
As for preventing other users from logging into your PC, is it your personal computer that you have on the Domain? Or a Company computer? Company policy may be that Domain Users have the ability to log into any computer on the Domain. You'll have to check with your IT Department/Network/Domain Administrators on that one.
Come to think of it, you should probably check with them regardless. You may not have permission/privileges to install or run any type of monitoring software.