Windows on VMware

Since Windows was first activated on this computer, the hardware on the computer has changed significantly. Due to these changes, Windows must be reactivated within 3 days. Do you want to reactivate Windows now? [Yes] [No]

I got this pop-up when staring Windows today in VMware.

Was this due to the fact I switched my computer or that I use a different version of Linux as the host OS or due to the fact that I use VMware player now instead of the Workstation I had earlier?

Who cares?

Why does Microsoft care?