First, make sure V-synch is ENABLED. I don't know how to do this in your drivers. If you can't find the option, search the web for Powerstrip or a similar tool to help you ensure V-synch is on.
Second, you might want to try a different driver version. Although with WinME, I have no idea what to suggest. Did you update drivers recently? If so, go back to what you had before. If not, you can try going to the 21.x versions and see if that fixes it.