i am not able to install update or remove itunes and install newer versions, windows installer service cannot be accessed,

i am not able to install update or remove itunes and install newer versions,

its stops installing and a windows error is shown

i e :: windows installer service could not be accessed , this could occur if you are running windows installer in safe mode

or windows installer service is not correctly installed

the same error happens if i try to uninstall the itunes from the control panel- remove programmes option

im using windows 7 home basic 64 bit version

this eroor is not happening with any other programmes..

can someone tell me how to solve this issue

thanx

tushar