Don't give up just yet! Just had a bit of a google and got a couple of things you could try. First is open quicktime, click on 'edit' in the toolbar, then 'preferences' in the resulting dropdown menu, then on 'quicktime preferences' from the next menu, then on the 'advanced' tab. Look in the ''video' section and see if 'enable directdraw acceleration' has a tick next to it and so is enabled. If so, uncheck this option to disable it. Then make sure that the 'safe mode' option is NOT checked but that the other two options are. So it should just be the safe mode and 'enable directdraw acceleration' options that are NOT checked in the video section. I haven't got directdraw disabled, but read that doing so has worked for people.
Another thing to try is go into your add/remove programs (in control panel), and highlight quicktime in it. Then click on 'change' and then click on 'repair'.
Hope some of that works for you.