Cannot install or uninstall Apple Mobile Device Support

Question

Trying to help a friend whose original problem was she was unable to connect her ipod. When I checked devices I found it was using the microsoft USB driver. I was unable to persuade it to use the apple driver so resorted to uninstall everything as per support instructions and re-install. Had problems uninstalling something (maybe AMDS) as it kept rolling back but after several tries it went from the uninstall list after some kind of complaint about the user not being an administrator (not true).
Did not work when re-installed so tried uninstall/install again. This time it uninstalled cleanly but then failed on the install. I had a look around and most things seemed to be uninstalled OK but found that AMDS was still installed and registered as a service but had failed to start. I had no way of uninstalling it because it did not appear in the installed programs list. I thought that maybe if I could install it then I could then uninstall it. I read about splitting the install exe into seperate MSIs so did so and ran the AppleMobileDeviceSupport64.msi. This failed and when I subsequently ran it using msiexec I found the error was:
DIFXAPP: INFO:   Could not open file C:\Windows\System32\DriverStore\FileRepository\netaapl64.inf_amd64_neutral_bf78 5db627c6d127\netaapl64.inf. (Error code 0x3: The system cannot find the path specified.)
DIFXAPP: ERROR:  PnP Install failed. (Error code 0x3EE: The volume for a file has been externally altered so that the opened file is no longer valid.)
When I looked in DriverStore I found that the directory netaapl64.inf_amd64_neutral_bf785db627c6d127 didn't exist but there was another netaapl64.inf_amd64_neutral but a different suffix. I thought this might be the problem so saw that pnputil could be used to remove it so did so but it still fails with the same error. At this point I thought I had better stop digging and seek help. Any suggestions other than re-install Windows 7 gratefully received.
The environment is Windows 7 64 bit and the iTunes version is 64 bit 10.7.0.21.

Answer 1

Just in case anybody comes across the same problem I thought I would provide an update. Unfortunately everything I tried failed and I finally had to restore the laptop to factory settings.
I tried manually removing AMDS by removing the service with sc, deleting the files under Program Files (X86)\Common Files\Apple and cleaning up the registry using ccleaner. Tried the install again but it still failed with the same error.
I then installed iTunes to another 64 bit Windows laptop (this failed claiming it was interrupted (how I love iTunes) but it had loaded AMDS). I then copied the netaapl64... directory from this machine to the failing machine (needing to take ownership and change permissions on the FileRepository directory). I then ran the install again and this time it worked !!! BUT... the AMDS service failed to start! At this point I decided to throw in the towel. It was either that or throw the machine through the window.
If anybody else ever comes to me with an iTunes problem they will be quite surprised at the reaction of someone they think of as very mild mannered!