let's try this 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.
next, we'll try to get a fresh copy of QuickTime into your PC by doing a
repair install of
itunes.
switch off antivirus and antispyware applications prior to the repair install.
go into Add/Remove and select itunes. click "Change" and then click "Repair".
if the repair install goes through okay, restart the PC and try launching itunes again. does it launch properly now?