Why did this PS2 to USB conversion not work?

I have this older keyboard and mouse that still work great, but they have a PS2 connection. My new laptop, however, does not. So I got some PS2 to USB adapters from an electronics store. After plugging them into my laptop, Windows does not seem to recognize the units, they don’t work at all. Is there a step I’m missing? Do I need to download some new drivers?