Need help with my Opfor mod! - Mouse Bug Thread

Hello!

Firstly let me just state I'm new to ModDB so I apoligise if I'm posting this in the wrong place or doing this all wrong.

I'll get straight to the point. I've successfully set up my base mod folder along with Hammer so everything works fine. Except when I try to turn ingame, as in turn left or right, I can't turn all the way. I can turn about 90 degrees before hitting some kind of invisible barrier where my view can no longer go any further. This also happens when I look up or down. (I have made a quick video to demonstrate this: Youtu.be )

As you can see I can turn fully using the arrow keys too. I've been reading through countless forums for the past week trying to look for a fix or a solution. None of the solutions I've found work at all. Normal Half-Life 1 and Half-Life: Opposing Force work completely fine, I guarantee I've set up my mod folder correctly and precisely too. My friend suggested it could be a corrupt file, I've validated both default Half-Life and Opposing Force several times and tried replacing my mods files. I've tried reinstalling, resetting up the mod folder, changing my mouse, changing mouse options in the config, etc etc. I experimented with using half-life's client.dll file and there was no mouse issue, which lead me to believe it may be the opposing force client.dll that's corrupt or not wanting to work properly. I'm unfamiliar with these kinds of files and problems and I was hoping someone may have a viable answer or fix to this as I cannot possibly progress my mod using opposing force assets.

As I said, I apologise if I'm wasting anyone's time, I'm out of options and I'm unsure how to go about this or what to do in general. Please can someone help me ;n;

Thank you

-Abaddon