I just came across a nifty little tool that I’ve added to my thumb drive when fixing computers. Its called TCPview from SysInternals and Microsoft. Its basically a netstat on steroids, but has a cool feature I like, which lets you send a reset packet to close connections to open ports you may not want to communicate with. This could come in handy if your machine had been attacked and is listening on some port you want to close and inspect further. It will also tell you the executable that opened the connection so you can track it down and remove it from your system.
http://technet.microsoft.com/en-us/sysinternals/bb897437.aspx