Securing my MT4 WKST

I use NT4 WKST and I also need to login to a domain (at work). How do I secure my wkst so that no one else can login using their domain account and password (not to my local machine)? Right now no one else can login to my local machine but someone can login if they have domain account with privileges.

Thanks for any info you can provide.

-Rich
richv@drexel.edu