Use windows update to install DirectX 11.1 for Windows 7 SP1 with Platform Update for Windows 7 and Windows Server 2008 (KB2670838). The game has a DirectX 12 API for Windows 7 similar to how WoW has a DirectX 12 API for win 7 but I think it needs 11.1 via KB2670838 first.

After installing 11.1 I could start the game but I still had crashes. A tip on another forum advised to delete the folder C:\Users\<insert your username>\AppData\Local\CD Projekt Red\Cyberpunk 2077. After that folder was deleted game runs fine (for me at least - your mileage may vary) - note you will need to go into control panel > appearance and personalization > folder options and show hidden files and folders in order to see this folder.

This info was taken from steamcommunity forum. Very big thanks to user N7 Cat, because after 10 hours of struggle for me, the game finally launches and works on Win 7.

Thanks a bunch for this post. I was having my graphics driver (1070) crash and remove one of my displays (two monitor setup) or having my system (Windows 7-64) completely lockup requiring a hard reboot as the keyboard was completely non-responsive. I was unable to run the game.

I did what you said and downloaded KB2670838, but when I ran it, it said it was already installed on my system. I then deleted the directory C:\Users\<insert your username>\AppData\Local\CD Projekt Red\Cyberpunk 2077.

After I did that I re-ran Cyberpunk and IT WORKED! First time the game has worked. About 5 minutes in and it is still working, so perhaps deleting the directory did it?

Anyway, thanks again, greatly appreciated.

[addendum] Well it works some of the time, say 10-20%. The rest of the time it crashes requiring a hard reset, or removes my monitor from the system, but doesn't crash the system.