So I watch various movie files but mostly .avi but no matter what kind of file I'm playing quicktime just keeps crashing suddenly. I just upgraded to a new iMac (10.5.1) from an eMac. On my eMac I used mplayer mostly but that doesn't work well on the iMac so I switched to QT (and had to download a codec to play files I previously had no problem with) . I am annoyed that I bought a new, stronger, faster machine and it can't do what my old eMac did, which is to easily watch some basic movie files! I can't believe something so basic has turned so complicated. Any suggestions?