how do i backup my ipad to my pc?

If you explain exactly what the problem is, it might be helpful.

Connect the iPad to your PC with the cable.

Launch iTunes

Right Click on the iPad name under the Devices heading on the left sidebar of iTunes

Select - Backup - from the menu that pops up.

Crystal ~ Welcome to the Support Communities. You can find several step-by-step guides by entering backup iOS in the first search field here:

http://support.apple.com/kb/index?page=search