After I start the game and press the keyboard or mouse at the "press any key to start" prompt, the game will not let me make any selections on the main menu. It's as if it no longer sees the mouse or keyboard.

Do you have a controller connected? That seems to disable keyboard and mouse.

I never use a controller so that does not fix my issue.

THANK YOU for that tidbit - I ran into the very same issue, and I don't *exactly* have a controller connected; I do, however, always have a razer Tartarus hooked up to my rig, and I guess it's ...controller-adjacent..? Once I disconnected that, I could suddenly navigate the menu - I got into Settings-> Gameplay and turned Controller to Off. Then I reconnected the Tartarus, and everything is now peachy. Counterintuitive, but it worked for my setup.

Here's hoping the OP similarly has a random peripheral causing this behavior -

Just using a regular mouse. Thanks anyway, after two hours of trying to get it to work I asked for a refund on GOG.

Thanks, SqLrob and Kidsghost. I only have my wireless keyboard and mouse connected. The strange thing is that the game sees them and lets me progress to the main menu using either of them. It's only on the main menu that they are not recognized. Thanks but don't use a controller Thanks, but I don't use a controller.

Thanks, guys. I'm such a bonehead. I had a dongle for a wireless controller that I had forgotten about plugged into a USB hiding in the back. I unplugged it, and like you both said, "Everything works." Thanks again for the help!!!