Computer is being hacked aol told me

1ST how do i find out is my computer being hacked? How can I protect my computer from beibg hacked? Aol sail someone hacked my computer and they just advised me to continue to keep changing my passwords and I change them pretty frequently anyways. Can someone help me wit trying to get these bleep bleeped to stop hacking in my computer and let me know what I can do to protect my computer and my info from being exposed?