Managed to solve it using the script below .
IIS6Prompts for Login but will not let users in
Some site specific settings may affect how IIS 6 works with itsapplications pools see the attached Microsoft post.
Running the below command should correct this
cscriptadsutil.vbs set w3svc/NTAuthenticationProviders "NTLM"
I am not sure about while using IIS but at the time of Web services..You should have to delete the all registry of the privious virsion installed.
Try this: Uninstall the your current version and delete all the registry details then reinstall the new QV version and check.
It may works in your case also.