Just changed your hardware quite a bit, or have a lot of removable devices you use that you no longer need... and randomly have some obsession with keeping things tidy. I cannot promise you that it will speed up anything.
* Open an Admin Command Prompt (right click on cmd, and select run as Administrator)
* type 'set devmgr_show_nonpresent_devices=1'
* type 'devmgmt.msc'
* select show hidden devices
* Now you can see disabled, unused drivers and remove them.