Crash on start up when launching Opposing Force (Fatal Error)

[MrDemonic]

Everytime I try and start up Opposing Force, it crashes on start up with the error message "Fatal error W_LoadWadFile: couldn't load gfx.wad". I have tried verifying the game files, reinstalling the game, reinstalling Half-Life and then Opposing Force and, even restarting my computer. Googling the problem hasn't brought up any decent results.

I am not sure why this is happening as I managed to play this perfectly fine a few months ago. But after trying to boot it up for the first time in a while seems to have caused this.

Any help with this? Thanks.

[Hell-met]

when you say you reinstalled, did you delete everything manually or only used steam's "remove local content"?

[MrDemonic]

Remove local content. I guess I should try just deleting everything in the Opposing Force installation folder manually?

[editline]28th March 2014[/editline]

Just realised that it doesn't have it own folder. I'll try deleting the whole Half-Life folder minus the save folder and see what happens.