okay. here's what we'll try first.
Download and install the Windows Installer CleanUp utility. then use it to clear any existing
QuickTime installation configuration information from your PC:
Description of the Windows Installer CleanUp Utility
Next, we’ll manually remove leftover program files and folders.
1. On the Start menu, click My Computer (or double-click My Computer on the Desktop).
2. In My Computer, open Local Disk.
3. Open Program Files.
4. Right-click on the QuickTime folder and click Delete from the shortcut menu.
5. Navigate to C:\Windows\system32\.
6. Remove the files QuickTime.qts and QuicktimeVR.qtx.
7. Restart your computer.
now try another QuickTime install. does it go through properly this time?