As already mentioned …
Without knowing what you may have installed, misconfigured, or otherwise done to contribute to the issues you’re experiencing, any specific insights are difficult to magically will into being, and likely to be time intensive; the game of 1000 questions.
The fastest way back to normalcy seems clear. 
The KVM
No matter the relative quality of any hardware or how long it might have admirably performed it’s function, I’m afraid that Murphy’s Law always prevails; there may come a time when that hardware fails, or falters.
Off topic;
Many of us are to varying degrees; either by circumstance or necessity (but seldom by choice).
Have you considered multi-booting with Windows and Manjaro on the same computer (but separate disks)?
Some time ago I authored a guide for doing just that;
I hope you find it useful at some point.
Regards.
[Multiboot] Windows and Linux on Separate Disks