Oh, wow, okay.

The computer that Bee selected is way overbuilt for what you need, but it's probably the best deal on a new computer that you're going to get.

SSD are still kinda pricey, but if you want one, here's a 800$ laptop on cyberpower PC.

https://www.cyberpowerpc.com/system/Tracer-III-15-Xtreme-100

Again, way overbuilt for what you're doing. You might want to consider getting a non-gaming computer, or something used if you want to shave off a few bucks. just keep the game's specs in mind.

https://www.systemrequirementslab.com/cyri/requirements/myst-iv-revelation/10249

As for dos games on windows, no clue.

EDIT: realised that the remastered myst is called "real myst," and that has specs that are much closer to what Bee and I recommended. That's probably as cheap as you can go.