Infected with Botware?

I have had the following symptoms on my computer for some time.

My browser loads up and almost crawls to a stop.

Sometimes if I have something going to the speakers the sound is all chopped up like there a thousand processor interrupts going on.

My processor fan is blowing at max speed as if the processor is working its little tail off.

Sometimes the browser (FireFox) crashes, I get the blue screen that says, "your computer has encountered a problem and needs to reboot." Then it gathers data and reboots.

If I invoke the Task Manager during these situations, the load up will suddenly back off and I never find anything obvious, though honestly I probably wouldn't know the culprit if it bit me.

I am running Norton Security Deluxe and Malwarebytes Premium. Neither has reported anything.

I have learned that these are signs of a botware infection and I could be a zombie.

How can I find out if I am infected or not and if in fact I am a Zombie, how do I fix it?