After installing get 403 Forbidden Access

installed wordpress using the platform installer
windows server 2008 IIS 7

PI installed PHP as well as mysql and then wordpress
installed wordpress into blog subfolder on a site

after installing and clicking the login link i got an error 403 Forbidden Access

when i navigate to the main blog folder the site runs but as soon as i click the login link i get the error again

i found numerous references to similar issues and tried a number of the proposed fixes (setting the default document, tried rights on folders, changed apppool user, etc)

for testing i installed wordpress into another site on the same server and it does not have the same problem

i cant think of anything special on the site that does have the issue

Any ideas what we could try to make this work? I did try to reinstall wordpress several times btw

thanks

Mike