Just upgraded to Win10, before I was using Win7. The game was working absolutely fine with Win7, but now with Win10, after playing for a short while the screen starts tearing like crazy.

Is there some basic stuff that I need to do to Windows 10, to get it to play good with older games? Or is this just RTCW only, and regardless, how can I fix this?

Is this happening with the vanilla install from the GOG installer or are you using an engine port? Personally, I started playing the game with ioRtCW and that has been fine for me.

Hmm, thanks for the reply, I presume I had been using whatever default GOG installs it as. Regardless, the problem solved itself a few days after I originally posted this topic, when I reverted to Windows 7, because 10 turned out to be a piece of garbage that routinely installed new nvidia drivers that were broken and would not let me tell it to stop.

Glad you got it sorted.

As for the Windows 10 issue you describe there, I'm a Win10 user with an Nvidia graphics card and it didn't try to install new drivers for me. Shortly after I got the PC (it was new in February), when I did come to upgrade my graphics drivers (which I always do manually), I used the Guru3D Display Driver Uninstaller (DDU) to fully remove the old drivers in safe mode. This utility also has an option that you can select to prevent Windows from downloading display drivers automatically. Then on booting back into normal mode I was able to install the latest drivers as a clean install. Maybe this will help when you do next come to upgrade your drivers and/or OS?