If you reformat your pc, you wipe everything clean. You won't have any more viruses or adware... you won't have anything on your hard drive. Well i guess technically you still have stuff on your pc, but its moved so it would be over written. To totally wipe it clean clean youd have to use one of those programs i've seen others advertise about. They overwrite the data so it's gone.
Reformat the drive completely. You'll loose all your data, but you'll start off on a clean slate. It's the best thing you can do prob.