I recently just learned of ReactOS, a Free and Open Source Operating System that has been in the works for over 20 years and aims to be able to natively run Windows programs and drivers. The program is still feature-incomplete alpha software, but I thought I'd give it a try in Virtualbox to see if I can run Winlink in it.

TLDR:

• First step: I downloaded the BootCD (not LiveCD) of ReactOS 0.4.13 and saved it.

• I used Virtualbox 6.1 under LinuxMint 20 XFCE.
• I created a new machine:
  
• I named it “ReactOS” and the version pre-populated to “Windows 2003 (32-bit) on its own so I left it there.
  
• I doubled the RAM to 1024MB
  
• To load the “install CD”, click on the word “Storage”:
  
• Select “Empty” and click on the CD icon.
• Navigate to the file ReactOS-0.4.13.iso and you should see:
  
• Back to the first screen, you can now start the machine.