I can't get php to work with iis 8,although I configured it properly with fastCgi.it used to work with no problems,but once I upgraded from windwos 8 to windows 8.1 preview,I can no longer make my php applications work on iis
Windows 8.1 is still in preview. If you cannot get it working as you wish, you can wait for the final release.
check the php.ini file and make sure the rest of the software stack is ok
I agree with lextm, you should wait for the final release of Windows 8.1