Is it possible to run two Windows programs on one computer?
I have a new Windows 11 computer with an SSD drive – I can also install an HDD drive – would that work with Windows 10 in addition or can I run Windows 10 and 11 side by side or at the same time or only with two computers and a switch box?
Not at the same time. But you can both boot from it. But with a VM you can run it simultaneously
Installing and alternately operating is an option.
If the “current” is to be used, this would be possible via a virtual machine, so that Windows 11 works on the computer as a host and provides a part of its RAM and the CPU core for a guest system, which can then be used by a virtual machine for Windows 10.
But make sense only if there is a corresponding need. Otherwise better separated than parallel installation or on a separate computer.
ok- yes with the switchbox okay
You can install and run Windows 11 VirtualBox in a Windows 10 virtual machine. Then both diapers run simultaneously.