Tried installing itunes 10.5 and recieved this error An error occured during the installation of assembly 'Micrsoft .VC80.CRT .type="win32" ,version="8.0.50727.6195".publicKeyToken="1fc8b3b9a1e18e3b".processorArchitecture="x86"'. Please refer to Help and

I am using Window Vista 32bit and have the same problem. After trying uninstall, reinstall, ccclean registry, over and over again and still cannot install itune 10.5. And finally concluded that this might be a registry corruption problem. The following steps is what I did to fix the registry isssue and get my itune 10.5 installed. - Run Window update - and check the history file, if you see some failures in previous updates, there is something wrong with the registry. - un-install all the apple related software (itune, safari, boujour, apple update, etc). - For Vista 32bit, go to the following link and run the script to clean up the registry. I am not sure if other WIndow OS will work or not. http://windows.microsoft.com/en-US/windows-vista/Windows-Update-Error-8000FFFF - run the Fix-it script. you have to select the Agressive mode (even thou the pop up window advise not to do this) in order to clean up the registry. When I try without checking the box, and it did not fix the problem. - reboot PC - Run window update. It will discover a lot of old updates that need to be installed (I suspect that the fix it script delete a lot of stuff in the registry and removed previous updates). I got 53 updates that need to install. - run the update and wait for a longtime (mine took ~2 hours). - reboot PC - run cccleaner - reboot PC - install itune 10.5 Now it works. Hopefully other window OS has similar step to fix this. I can only say it works for me using window Vista 32bit. and so far, my PC works correctly.

The only resolution I found that worked on my 32-bit Windows 7 was to reinstall iTunes 10.4.1.

Windows 7, 64bit here. I found pretty much what others are finding-- I had a failed Windows update that I couldn't do anything with. I tried pretty much everything under the sun including an in-place upgrade, but nothing worked until I re-installed Windows. It's frustrating that 10.5 doesn't work when 10.4 clearly does, but I think my system is in a better place as a whole with that failed (corrupt?) update cleared out of the way. Yeah, it's a lot of work just to get iTunes to work, but it might save additional headaches down the road.

i'm sure lots of other people (like me) are resisting the reinstall windows option but like JPRobbie, i also reinstalled windows last week and agree that my system is better off for it. i eventually just bit the bullet because i noticed other software updates were also failing so i said, i've had enough. one lesson i also learned is that i'm going to do my system updates in batches and not allow windows to just apply them. i'm going to control the system updates so that there aren't as many "system restore points" to manage if they were batched together.

good luck.