Audit of Event Logs

I'm trying to determine if there is a way to detect if someone is logging on to your machine. Basically a domain admin - or it could be someone else I suppose. I generally do a "NET STOP SERVER" when my machine is re-started or turned on - (so at least the "normal c$ shares are unavailable) - but I've recently taken a new role in the organization where it is "believed" that my new job responsibilities no longer warrant domain admin authority. I understand that I can manually review the event logs on my machine - and I assume I might notice something there - but I'm really looking for an automated solution - that detects when others have a session with my computer. Thanks for any help.