Open ports on a remote machine
 

I have been trying to help a friend fix a problem on his windows machine. She installed VNC and I have been using to share her desktop and work through some problems. However the VNC has mysteriously stopped letting me in. She has recently installed and ran Avast antivirus and I can only guess that this has stopped her machine listening on port 5900.

Is there a tool I can use that will show me waht ports are open on a remote machine given that I know it's IP?

You mean a port scanner? Try looking up nmap.

Thanks a lot
 

Thanks a lot, that is exactly what I was after.