i cannot get this game to work...the screen just flashes. anyone else have this problem? it's weird because tf2 works fine and it installed from the same damn disc. thanks. i love this freakin' game and wanna play it again!!
I have Portal on my machine and it works. I'd go with what mi1ez said. Reinstall the application and see if it works. Also, I'm assuming you must have purchased the boxed edition. Have you looked to see if there have been any updates to the program since you purchased the program? I know with the Steam they download any updates that exist, so mine as soon as I downloaded it via Steam.