Here are the steps to revert to the previous version of Quicktime:

1. Click on START and then ‘Control Panel’
2. Click ‘Add/Remove Programs’
3. Find Quicktime in the list of programs
4. Click remove to remove the current version of Quicktime
5. Download Quicktime 7.6.2 here.
6. Install Quicktime 7.6.2 and restart your computer.