How do i setup .htaccess for a specific directory to not allow specific types of file extension and NOT ALLOW any execution of a the files within that directory?
A .htaccess file could only control the behavior of the webserver.
If you are speaking about
CGI script, that get executed, than you should configure your CGI directories correct.
Apache does not execute any other file then CGI's.
To forbid the execution of files on system level, you have to remove the
x flag. But be careful. If you remove the
x flag from a directory, you wont be able to enter it.