Quicktime.
You won't be able to play any .MOV or .mp4 files if you remove Quicktime.
not to be rude but its called quicktime PLAYER so it only plays files
You need to add the free Flip4Mac player plugin (See links below) to Quicktime then you can view Windows Media files with the Quicktime player..
A computer will be unable to play videos if it does not have the appropriate player and codec to decode the files. There are a variety of media players like VLC and QuickTime which are designed to play these files.
QuickTime is Apple's media player and can play a variety of media files such as AIFF, WAV, DV, MP3, MP4, MOV other formats can be played with the addition of plugins.
Quicktime plays MOV and QT files. If you have Windows 7 media player, then you can't play QT or MOV files on it. You need to convert the files to one of the following file name extensions:.asf, .avi, dvr-ms, .m1v, .mp2, .mp2v, .mpe, .mpeg, .mpg, .mpv2, .wm, .wmv
There is: Windows Media Player, GOM player, Quicktime, etc. I use Quicktime even though I have Microsoft, because it plays almost all media files.
Go to http://www.media-convert.com/ and do it online.
Apple Quicktime and VLC player are decent player and can be obtained by downloading from the related link.
You can drag QuickTime videos from your files to the iTunes movies section, and then sync your iPod with iTunes to get it on your iPod.
I had tried for months to stop the question mark showing up. The only thing that worked for me was to uninstall Quicktime. Low and behold ... it worked! Bit extreme, but ... result! Finally! (Now I just hope I don't have to play any Quicktime files!)