Is the menu bar at the top of the screen translucent? If not you may find that the graphics driver didn't get installed properly and it is using the processor to do the animations rather than the graphics card. This happened to me as well.
As a check try and add a new widget to Dashboard. If the graphics drivers are installed and working properly you should see a watery ripple as the widget appears. If it just appears, then the drivers aren't installed. Run the NetbookInstaller again (and again) until the menu bar is translucent.
Hope that helps.