I have just installed the latest ati restricted drivers
using these instructions

The installation went without a problem; however, after the installation, video playback in vlc or mplayer (avi files) now exhibits significant flashing, so much so that video is now unwatchable. I would really appreciate if someone can answer a few questions.

1. I had the ubuntu's repository fglrx installed (older version) before attempting the manual installation, could this be the cause of the problem?

2. If that could be the problem, how can I clean up my system so that it is 100% clean of ati drivers before attempting to install again? (I tried to search for an ati uninstaller but there doesn't seem to be one)

3. Actually this is almost the same as the previous one. How can I uninstall the current version of fglrx so that I can revert back to the previous ubuntu repo drivers?

Thanks for your help!