🙂 Thank you!
The basic plan will be to uninstall
both QuickTime and Apple Application Support this time, and then reinstall QuickTime (which should also reinstall Apple Application Support). We'll take a few other explicit precautions along the way, too, just in case.
*Preliminary phase*
First download and save a copy of the QuickTime installer to your hard drive. (Don't run the install on line, and don't start the install just yet.) Get the version of the QuickTime installer that doesn't mention iTunes.
http://www.apple.com/quicktime/download/
Now quit Safari if you have it open. (The 4.0.4 version of Safari also uses Apple Application Support, and will interfere with the Apple Application Support uninstall if it is open.)
*Uninstall phase*
Head into your "Uninstall a program" control panel.
Uninstall QuickTime.
Uninstall Apple Application Support.
(Fron now on, until we reinstall Apple Application Support, your Safari 4.0.4 will no longer be able to launch.)
Next we'll remove any left-over QuickTime or Apple Application Support program files.
Restart the PC.
In "Computer", navigate into the C:\Program Files\ folder. Right-click on the QuickTime folder (if it still exists) and select "Delete".
In "Computer" navigate into the C:\Program Files\Common Files\Apple\ folder. Right-click on the Apple Application Support folder (if it still exists) and select "Delete".
In "Computer" navigate into the C:\Windows\system32\ folder. Check to see if there is a QuickTime file or a QuickTimeVR file. If either of them still exist, right-click on each and select "Delete".
Empty your recycle bin.
*Reinstall phase*
Restart the PC. (If iTunes is installed on the PC, you'll probably receive a message at this stage saying that iTunes will not run because Apple Application Support is missing. Click through the message.)
Do not open any applications.
Disconnect from your network and/or the Internet.
Disable all security software (firewall, antivirus and antispyware).
Now start the QuickTime install by doubleclicking the QuickTimeInstaller.exe file you downloaded earlier. (This install will also reinstall Apple Application Support.)
Reenable all security software prior to reconnecting to your network and/or the internet.
Does the install seem to go through properly? If so, try launching QuickTime again. Does it launch without the error message this time?
Does Safari seem to behave a bit better too? (Difficult to tell, of course, given that that's an intermittent problem for you.)