How to repair the Apple Mobile Device Support

Today I installed iTunes 10.5 on my 64-bit Windows 7 but it did not work well. It crashes everytime I check the backup of my mobile devices. When I conneted my iPhone to my computer, it didn't show in iTunes. Then I checked task manger and noticed that AppleMobileDeviceHelper.exe always jumped out, showed for about 3 second then disappeared again.

So I uninstalled Apple Mobile Device Support. And everything just worked just fine, except all the mobile device functions were disabled.

I have tried uninstalled iTunes, QuickTime, Apple Software Update, Apple Mobile Device Support, Bonjour and Apple Application Support, deleted all the files connected to Apple, then reinstalled iTunes. But the problem was still there.