Itunes has stopped workin

Question

recently i was promoted to upgrade to itunes 8. i updated itunes and it was working fine, a day later i setup genius for my library. itunes was still working fine, but 2 days later when i turned on my pc i got a message saying *"itunes helper has stopped working"*. i tried to open itunes than i got this message*"itunes has stoped working"*. i tried to repair it. i unistalled/reinstalled it 3 time, but nothing. i even went to control panel and clicked on quicktime and than clicked repair, it went on to try to repair quicktime but right before it was almost finished trying to fix quicktime i got another message that read *"windows installer has stopped working"* so now im completely stomped. some one please help

Answer 1

If QUicktime doesn't work then iTunes cannot work as it requires a functioning QUicktime.
First, have you ever installed any of the following:
ACE & K-Lite mega codecs package, QT alternative, Storm codec, WinAVI video converter
If so you must uninstall them before proceeding - these are notorious for causing QUicktime problems after an upgrade.
Then we will go for a removal of iTunes and related programs with an installer clean up of any programs that do not uninstall properly:
Download a fresh copy of iTunes and the stand alone version of Quicktime (the one without iTunes)
http://www.apple.com/quicktime/download/win.html
http://www.apple.com/itunes/download/
Download and install Microsoft Installer cleanup utility, there are instructions on the page as well as the download. Note that what you download is the installer not the program – you have to run it to install the program.
To run the program – All Programs>>Windows Install Cleanup
http://support.microsoft.com/kb/290301/
Now use the following method to remove iTunes and its components:
XP
http://support.apple.com/kb/HT1925
Vista
http://support.apple.com/kb/HT1923
*If you hit a problem with one of the uninstalls don't worry*, carry on with the deleting of files and folders as directed in the method.
When you get to deleting Quicktime files in the system32 folder as advised in the method, you can delete any file or folder with Quicktime in the name.
Restart your PC.
Run the Microsoft Installer Cleanup Utility. (Start > All Programs > Windows Install Clean Up)
Remove any references you find to the programs you removed - strictly speaking you only need to worry about those programs where the uninstall failed.
Occasionally QUicktime doesn't show up properly in the cleanup utility, so if you don't see QUicktime and it didn't uninstall properly, look out for numeric entries that could be QUicktime version numbers e.g. 7.5.
restart your PC
Install the stand alone Quicktime and check that it works.
If it does, try installing iTunes.
I am hoping that the message about WIndows Installer not working was related to an install going wrong rather than a general problem with Windows installer.
If things don't work out you need to give as much information as possible about what went wrong including the full text of error messages and error numbers if any.