After installing Lion all my stuff was still there so I erased everything form Disc Utility and then downloaded Lion again (that was the only way I could think of having a clean install) anyway, before doing all this erasing re-downloading thing, I was able to tap twice with one finger and move windows, now (after the erasing re-downloading) if I don't thick the box "Three finger drag" in the Trackpad menu, I cannot move anything.