How can I slow a game down?

I'm trying to play The Binding of Isaac on my laptop, but the game is just running too fast for me. I can slow it down if I unplug my laptop, which I believe throttles my CPU. I'd like to find some generic way to artificially slow a game down.

Questions similar to this have been asked before, but I don't want to have to load up a VM or pay money for a solution. Is there some way to slow down or throttle my CPU slightly in order to make games like this slightly easier?

I figured out what was happening when I unplugged it that effectively throttled the CPU, go to:

Control Panel -> Power Options -> Edit Plan Settings -> Change advanced power settings

Look for "Processor Power Management" and you can edit the settings from there.

It would be nice if there was a quicker/hotkey way to do this though, as I don't like to have to keep digging back into the control panel.

You guessed correctly why the CPU performance changed, so I won't comment on that any further.

Historically however, there was a similar problem with older (DOS) games running too fast, because they weren't built for modern processors.
For this reason, some utilities able to throttle the CPU emerged. You can find some with a quick Google search.
Keep in mind what the webpage says, though - this approach may not be suitable for modern games and the newest processors.