QEMU does a pretty good job at pretending to be a 1997 computer, or a 2025 computer, and it seems to work well to run QEMU inside of QEMU already, so should be somewhat likely that old virtual machines can be kept alive by running inside of increasingly deep levels of virtual machines running inside of newer virtual machines.
Legal, non-free, operating systems to install in those virtual machines is trickier. No old freeware version of Windows (yet?). Installing a minimal Linux distribution with WINE, for games that can be made to run in WINE in QEMU, might be the most stable way to preserve a 1997-era game. Except for 1997 DOS games (there were surprisingly many still being published in 1997!) that run so well in DOSBox(-X).
Legal, non-free, operating systems to install in those virtual machines is trickier. No old freeware version of Windows (yet?). Installing a minimal Linux distribution with WINE, for games that can be made to run in WINE in QEMU, might be the most stable way to preserve a 1997-era game. Except for 1997 DOS games (there were surprisingly many still being published in 1997!) that run so well in DOSBox(-X).