video lost

Hi,
I installed Ace Mega Codec Pack for Windows XP. It would not work, I tried to delete it, it would not delete and system restore would not restore.
I no longer have video (only sound) on Real player, quicktime, medial player and when I try to start a dvd or avi with one of these programs ace Mega codex pack tries to load.
I deleted media player and installed media player 11, still no luck.
My two problems are getting back my video and ridding the computer of ace Mega trying to start up everytime I try to watch video.
Any help would be appreciated.