Getting IIS Server Error 500 is it PHP or Server?

[vicodin]

Ok so i have a IIS server running with php installed. I also have a my SQL server on the same machine as IIS. BTW the server is crap but it's only a dev. server. So I am sending a MYSQL query that is checking against 65,000 MYSQL entries and it can never finish. I get a Sever 500 error from IIS. It goes about 45 seconds and then dies with the 500 Error. I changed my php timeout to like 300 seconds but is there anything else in PHP or in IIS i can change so it doesn't give me this 500 error? Thank you for the help!