I went through the same exercise. What I found out on mysql 5.0 is that the php extensions for mysql are not included in the mysql 5.0 installation. I went to the following link:
http://dev.mysql.com/downloads/connector/php/
and downloaded the windows 5.027 connectors for both mysql an mysqli and installed as directed. There are directions on the bottom of the page on where to intsall the files.
I did get a no database found error after this, but I reset the cgi.fix_pathinfo in php.ini = 0 for the initial setup. Probably will set it to 1 to get permalinks to start working, but haven’t made it that far.
I probably have a good 3-4 hours into this. After reading this post I realized that the extensions are not included in mysql 5.0 install. Good Luck!
