Switching hdd’s?

I have a 2009 Asus and a 2012 hp. They both have windows, the hp with windows 10 and the Asus with windows xp, could I change the harddrive over from the asus to the hp and instal a new windows10? I don’t have the powersupply for the asus yet and want windows 10 to already be installed when it arrives or do I have to wait because of system compatibility and incompatibility stuff between the two?