CCleaner is known to sometimes cause issues if you always click "fix all registry issues". It is also prone to bugs and should be used carefully. Anti virus software sometimes decide to delete completly safe files that are even nessesarry for software to function properly, steam is also an intrusive software that takes many liberties that can clash with other software. Just saying: sometimes computer maintenance can be a b1tch. Usually it all works fine, but then suddenly problems start piling up for no apparent reason.
Yeah, I too prefer win 7 over 10. I've had a lot of strange behaviour from my win 10, spent a lot of time modifying the operating system to smooth its behaviour out, got it pretty good now, but I keep asking myself when it will bug out on me again, at the next OS uptdate perhaps.... Windows 7 was rock solid through all Microsh1t updates when compared to win 10.