I think my MacBook Pro has a virus. Help!

My computer was working perfectly fine the night before...I opened it up this morning and the mouse, using the trackpad, was jumping everywhere, dragging documents across the screen, opening up applications, and just going in the oposite direction I intended for it go!

Itried resetting my SMC, I removed my battery to check to see if it was swollen (it is not), and I've tried countless times to put it to sleep, restart it, hold L-Shift/Control/Option before starting it back up again. Nothing has fixed the jumping mouse.

I THEN realized: this ONLY happens on my personal account. When I enter into the guest log-in (where I am typing and doing all of my work), my computer works perfectly. Even if I don't log into my other personal account, but just click on it where it asks for my password, even then, the mouse starts jumping. This is what has lead me to believe my Mac Pro has a virus.

I do download/torrent movies and shows off of torrent websites, possibly opening up windowns of opportunities to download a virus though I always check that is has good reviews and is approved by others. I'm not sure how this happened.

PLEASE HELP. I hope I can get it back to normal without spending a fortune. (I do not have Apple Support).

Thank you so much for reading and any advice will be much appreciated!