Ok, to stop siad on W7: NOT USING TASK MANAGER
Using CMD prompt, change directory (cd) to - example command line: cd C:\Users\XXX\Desktop\Sia-UI-v0.4.2-beta-win64\Sia-UI-v0.4.2-beta-win64\resources\app\Sia (or wherever you have you SIA 4.2 directory) in my case it is on my desktop.
Then type: siac stop
Got the message: Sia daemon stopped
Restarted wallet, unlocked it, all good.
Just not sure if I did not do the above step to close siad, and I do a PC restart will that corrupt file again? I don't feel like testing that lol.... in the event of a power failure, PC shut down etc. that could result in corrupt files again.... we will need a better way to totally close siad in the future so there is NO risk of corruption in any way

You can shift+right click the SIA folder and open a command prompt with the location already set.
Or just make a batch file.