Question about which tools to use, bugs, the best way to implement a function, etc should go here. Don't forget to see if your question is answered in the wiki first! When in doubt post here.
Not in front of an XP machine at the moment, but IIRC, you can right click on My Computer (whether it's on the desktop or in the Start menu), select properties, and then somewhere on the tabs is a way to set environment variables, PATH included.