You need to run an emulator like STeem or Hatari. Both of these will run MSA/ST image files.
STeem can also run STX image files but you need to add the pasti.dll file to your system from what I remember.
Mega"SST" 12, MegaSTE, STE: Desktopper case, IDE interface, UltraSatan (8GB + 512Mb) + HXC floppy emulator. Plus some STE's/STFM's