IIS site will not open .htm or php files

Question

Platform: IIS 7.5 on Windows Web Server 2008 R2

I have a site that has stopped allowing .htm and .php files to open, behaviour with each file type in different browsers is as follows:

.HTM FILES

Firefox promtps to download IE opens fine Chrome opens it as plain text

.PHP FILES

Firefox display File Not Found IE prompts to download Chrome opens fine

This was working up until around a month ago, there are rewrites in place on this domain but we've removed them to see if it makes a difference and it didn't.

Other IIS sites on the same server work fine, we've compared the settings and can find no difference at all in configuration.

There is no .htaccess file in use although Helicon Ape is installed.

This server is also running Coldfusion 8 but this is configured for all sites so it that was the issue it should also affect the others but does not.

Answer 1

This turned out to be the MIME types in IIS - added the text/htm and text/html ones and it worked.