Reboot and clean my computer so it will run very fast

Rebooting your computer you need to power it off by pressing the power button off and make sure it is off but that's when you re assured that what ever was loading was closed.and switch it on again. Your computer will be successfully rebooted.thats my opinion just try that.ANDREW.

The process of rebooting is simply powering your PC off and back on.

I think, what you want is to clean out the computer. Very often its best to just back up your data, collect your installation disks and files and use your Recovery disks to restore the computer to factory settings.