Replying to Hd film problem

Alright. So my camcorder is pretty entry level, consumer hd camera, the canon vixia hg20.I've owned my computer for three years and it runs windows vista. When I upload video, it plays fine while in a standalone player a little glitchy sometimes, but when I attempt to edit footage in any form of editing software, it glitchs up and often freezes the whole computer. The camera shoots I think 1080p. Is there anything I can do to make it run smoothly?