Other Admin Hacking My Registry Etc.

While I’ve figured out other parts am at a loss on some–Been Reading for Days.

Other admin in NT4.0 PDC/BDC Server Domain is logging into my Win2KPro wrkstn. User ID is returning to mine but he’s using his account. (His profile left behind/then next day deleted)

I have nothing to hide. I figure he thinks it’s cool.We have several servers running all major MS products, VPN, Firewalls, etc.

How is he doing this? Can I trace what he’s doing and watch him without him tracking that he’s been discovered? Can he do this by RAS? Can he get to my E-Mail?