How did you try to uninstall LW? The correct way is via start > all progs > LW > uninstall. Uninstalling through add/remove programs can cause problems.
You could try reinstalling LW, then uninstalling it the right way. Have you used the computer's search to find & delete all LW files?

The popping up thing sounds a bit suss, you could have a virus. If you go to Norbiesworld, register & follow the directions for free computer help then Norbie will check out your computer. If you do have a virus, he'll be able to help you remove it