Computer hang up

[Conn88h]

My computer will play DVD's ok, but when pausing,or exiting the programe, my computer hangs up big time, resulting in a 'Restart'

This happens which ever Player I use, Realplayer,Win Media or WinDVD7.
I am not sure which type of files causes this problem, as video tutorials on Digital Photo magazine CD play back without any problems, I think these are AVI format, but not sure!!!!

Any help would of course be very much appreciated.

Nicholas Cooper ( UK )