I installed VM. During initial set-up, I must not have configured it completely because when I try to start it, I get the following: 'Fatal: No bootable medium found! System halted.'

Suggestions on proper configuration?

Also, upon reading the benefits of running tasks in VM, it leads one to believe that Linux is the preferred OS to use when doing so. Should all tasks be run in Linux or does it not matter which OS?

I installed VM.

Great!
But which one? Brand/version number?
On what operating system?
What were your intentions with it?

During initial set-up, I must not have configured it completely because when I try to start it, I get the following: 'Fatal: No bootable medium found! System halted.'

If you only installed a virtual machine program but nothing else, and you're not pointing to an (external) ISO or other image file, then you'll need to install an operating system inside the VM you want to run.

Also, upon reading the benefits of running tasks in VM, it leads one to believe that Linux is the preferred OS to use when doing so. Should all tasks be run in Linux or does it not matter which OS?

Depends on what you're actually trying to accomplish, so let's start there. What are you trying to accomplish? To speak with Johnny 5: need more input.

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