Remote access to display?

I have reason to believe a malicious user is remotely accessing my display, and am trying to detect any malware/activity that could suggest this. I've already run Avast! anti-virus on my HD, but nothing was detected. I connect to the internet through an ISP that dynamically assigns IP addresses: is there any way this user could eavesdrop on my display by knowing my IP address? Any recommendations for detecting a threat? Thanks.

I'm running Windows Vista Home Edition.

If someone is connect to your machine running remote desktop you would be logged of the machine until that user was logged back off. You can always turn of remote desktop in your system settings.

In some situations you will not be logged off ( eg support session/ Desktop sharing ) and you cant see that someone is using Your screen .

Check connections by running netstat -a You will se all Ip connected to You.( including softwares like www browser etc so don't Panic

Sometimes You may feel that someone is playing with your mouse - if it's optical then change mouse pad ( bad can cause moving cursor itself and You may feel observed. ) - strange but ive meet few times that situation.