my itunes played the videos without quicktime.after restarting windows,it is not able to play the same videos without quicktime.why?

I'd like to try doing a "Run as administrator" on your iTunes.

Quit iTunes first.

In Computer, open Local Disk C: or whichever drive you have your program files installed on.

If you have a 32-bit Windows, open the "Program files" folder.

If you have a 64-bit Windows, open the "Program Files (x86)" folder.

Open the "iTunes" folder.

Right-click on the iTunes.exe file and select "run as administrator".

Can you play the movies without the message, now?

This seemed to work. Specifically I had to right-click on the QuickTimePlayer file & choose "run as adminstrator" to get these movies to play.

Thanks!