The first thing I would try is installing QuickTime. See if that gets you any further.
We know nothing about your system or any otehr details, so this is not going anywhere. As a stasrt, trash the prefs, flush the cache, remove any third-party plug-ins and scripts. For anything else you wil lhave to provide exact system info and crash details:
As Mylenium says, we need to know a lot more if we're going to help you. Please provide answers to the questions listed here: "FAQ: What information should I provide when asking a question on this forum?"