I can't believe it! After a three year hiatus, I thought I'd drag the old Windows 7 HP laptop out of retirement and give SC4 another long overdue shot - I've been playing Cities: Skylines.
After all the trouble I had trying to get the game to run on Windows 7 originally, I was well annoyed to find I could no longer run the game.
Tried all the old tricks, went through numerous website, including Simtropolis, for solutions... nothing... until I spotted this 11 year old post...
Worked first time.
You are my new hero. I salute you, sir.