do I have to manually unload WindowsBlinds 10.74 every time after Windows loads up to the Desktop!?
If you apply the Default skin (the first skin) within WB, it unloads WindowBlinds and WindowBlinds will not load upon the next boot or login.
Come to think of it, the current version of WB is 10.82, you might try uninstalling 10.74 and installing 10.82 to see if it works any better for you.
Maybe the 3rd time is the charm- If the problem is purely having WB load at boot and afterwards WB works ok, you can keep WB from loading by holding down the [Control] key for about a second while you're pressing enter at the login screen. The default Win10 skin will load, then you can apply a skin through WB.