itunes updating problems

OK This has being happening for a week and now im gettin frustrated my itunes has failed to update everytime i go to update it to the latest verison and it says "Itunes installer has stopped working" so i uninstalled all of the itunes components excluding my music files of course and i went to reinstall it but i got the same message is there anyone that has any insight on this topic or suggestions that help in seeking the answer

 

My OS is vista and yes i have tried to manually install it from itunes webpage and the same thing happens i deleted the whole app just in case the components were not corrupted but no matter how i do it i alays get the same message and i tried to do a disk-error check and nothng happened after that either o i am at a dead end

 

I have try that and it installed but now when i open it and get another error "<iTunes: iTunes.exe bad image> C:\Windows\system32\dssenh.dll is either not designed to run Windows or it contains an error. Try installing the program again using the original installation media or contact your system administrator or software vendor for support." and i tried installing it again and have searched the support forums for answers and i have found nothing but the bright side is that now its on the computer which was because of the last reply (disabling the security features) but it seems to be the computer acting up