Some older games run too fast when you have a new computer.
If it’s a DOS game, you can just use DOSBox.
If it’s not a DOS game, you can’t use DOSBox. But there are other ways to slow down your CPU.
The PC Slowdown Page has several tools to slow down your processor.*
For example, to play SimCopter (an early 3D game created by Maxis), I had to use the The MS DirectShow SDK CPUGrabber, which is available at that website. Otherwise, the game would randomly crash.
*CPU and Processor are the same thing — but real geeks would know this! 🙂