Itunes not installing in win7 getting error 7

Hello,

Please help. Itunes 10.5 is not installing in my pc which runs on 32 bit win7. While installing it hung at publishing product information for about 20 minitus and then giving an error signal and performing a "rolling back action" and again it took arond half an hour at this position. finalling a message comes and saying " Service apple Mobile device failed to start. Verify that you have sufficien previlages to start system services" I given an "Ignore" at this point (as retry failed 2 times) itunes is installed but when I tried to open Itunes it giving an error message saying "error 7 ()windows error 217)"
Can any one help me?