Steam User interface not working.

[Mr. Ford]

I've had this game for a long time. But now all of a sudden the steam's user interface doesn't wanna work. I can't take screen shots or open chats to my friends. It works for my other games but not half life opposing force.

[Argyle]

Delete Clientregistery.blob in your Steam directory

Re-Accumilate files by Renaming the Half Life Opposing Force folder and running the game through steam

Re-Download the GCF files by copying method 2, and then renaming the GCF inside of Steamapps

Get CCleaner, go to its Registery Cleaner. Clean up your Registery.