After installing Media Player Classic on windows Vista, I couldn't seem to get it to act as the default video player even though all the settings in windows explorer suggested that it was the default player.
After alot of Googling, it seemed that others were experiencing the same problem, but I couldn't find any solutions. Although the default program for the .avi file type was Media Player Classic, avi files were always launching in Windows Media Player 11. This was driving me mad!!
I'd installed Media Player Classic which was part of the KLite Codec Pac, the version I installed was circa March 2006.
I simply upgraded my my version of Media Player Classic by downloading the latest stable version from here, then overwriting the original mplayerc.exe file from my
Program Files/k-lite codec pack/media player classic folder
After that, in Media Player Classic go to:
View > Options > Formats
then be sure the Video File checkbox is checked - this will set media player classic to be the default program for avi files in windows vista.
Hope this helps someone else!
Tim