To find if things are running in the background -
Open your Start Menu. In the search box enter - msconfig Click enter. Click "Continue" In the popup box click on "Startup" This will show all of the programs that are turned on when your computer is running. A lot of them are necessary but many are not. Be careful about what you click off. We have about ten that must be on and about 15 that we have turned off on startup- like Itunes, windows live messenger, quicktime. These run fine when we need the programs and don't have to be on all of the time.
Turn of all of your automatic updates. Go to security for Windows Updates and turn it off. Download updates when you have WiFi. Check all of your other programs and turn off updates.