Before object oriented programming, before threading, GUI applications were massive co-operative multitasking C switches:<p><a href="https://github.com/microsoft/winfile/blob/master/src/winfile.c#L486" rel="nofollow">https://github.com/microsoft/winfile/blob/master/src/winfile...</a>
I set up Windows 98 on an old Pentium III for vintage gaming. I had forgotten how simple, fast and "you have one job" this is. Definite install on my Windows 10 machines.
And if you want the neat, small calc.exe back, I used this: <a href="https://winaero.com/blog/get-calculator-from-windows-8-and-windows-7-in-windows-10/" rel="nofollow">https://winaero.com/blog/get-calculator-from-windows-8-and-w...</a>