So I was trying out this SweetFX thing, followed instructions I thought correctly, but now my game crashes no matter how I try & start it now. How do I remove anything sweetFX did to it? I've tried the remove option but errors out, I've removed the sweetfx files/folders in the game directory & still doesn't work.

Also I've tried doing what the txt help file or whatever said to like disabling overlays & the like, run as Admin etc. Nothing helps.

You must remove the sweetfx folder, d3d9.dll (and.fx) dxgi.all (and .fx) injector.ini, sweetfx preset.txt and sweetfx settings.txt. I'm guessing you used the configurator which I think it an awful choice as a sweetfx options go. xD