tom77,
Netbooks are not speed demons but certainly should be able to do email and skype without much problem. HP, as a general rule, makes some pretty good stuff.
Leave the .NET stuff alone. Removing that could cause you some grief. I wouldn’t worry so much about the size of the program but what processes are running in the background. AVG real time file and link scanning would be my first suspects. These are great, if you have the extra horsepower to do these tasks in the background but can slow things down if there is not enough CPU to go around.
Try configuring AVG not to do real time scanning, or even disable it temporarily and see what impact that has on performance.
-Fred