I can't open MOV. files on my new mac, please help

Hi I'm new to mac's and I love my new toy, but I'm having a little problem with transferring my video's from my old PC. I've tried manually transferring my mov. files from my PC hard drive to my mac. All the videos used to open up on the PC with Quick Time, now when I try to open them up on the mac it says QT can't open this type of file? Any ideas please