First, the premises: PHP loaded on IIS6 on Win2003 STD R2 SP2, PHP_5213 using FastCGI, MySQL_5145.
Customer sent me the site files, which I unzipped to C:\\InetPub
When moving files from one server to another and getting the blank page, check whether the code is using short opening php tags like instead of the full
opening tag. If it is and the original server has the following line in the php.ini file...
short_open_tag = On
but the new server has...
short_open_tag = Off
then the blank screen may be the result.