These settings will increase the amount of times your keyboard(s) spam a certain letter. Everything mentioned here works for Windows 8+ and newer. You will probably have to adjust all their settings though. Below, you'll find a way to access your keyboard settings.

Search "Control Panel" on your mainscreen. Find the "Devices and Printers" section and click on that. Find your keyboard on-screen and right click properties. If all of this was done correctly, you should come to a screen that looks like this. https://gyazo.com/8dd697920cc8ef1d51a3891c316a53db

It's already set to default settings. What you need to do is lessen the delay because repeat speed is already maxed out. If you wanna change it back, just go back and set it to normal and you'll be good to go again!

Control Panel>Devices and Printers>Keyboard Properties>Make your changes.