php question

Im in the process of putting php on my apache web server and the instructions say to add C:\php to my PATH System Enviroment Variable... wtf is my PATH System Enviroment Variable???

right click My computer->properties->advanced->environment variables

ok so under system variables i scroll down to Path and click edit, then in the variable value box do i just put in C:\php after the last one thats in there (%SystemRoot%\System32\Wbem)? And how do i seperate them? with a semicolon?

ok, well i did that but php doesnt work. I put the lines:
LoadModule php4_module c:\php\sapi\php4apache2.dll
and
AddType application/x-httpd-php .php .php3 .phtml
in my apache httpd file but now the service wont start, however if i take out the LoadModule line then it starts fine, also i had no idea where in the file to put these so i put the LoadModule with all the other LoadModule lines in alphabeticle order and i put the AddType at the bottom of AddType list where all the AddTypes were (there were only 3)

what am i doing wrong?

EDIT: i got tired of screwing with trying to call up php as a module so i installed it as a CGI and now when i call up phpinfo on my site i get an internal server error, in my error log it says Premature end of script headers: php.exe