Is the computer running, or ever run a Norton anti-virus product?
Download adw cleaner to get rid of adware.
I use Ccleaner, malwarebytes and advance system care. All are free. My anti-virus is AVG free.
I have a spare PC and a spare laptop that I use for "buggering about" with. I've tried allsorts and slowly learned from some mistakes. Ubuntu is the way ahead if you want a quick operating system on an old spec computer. The learning curve could outweigh the benefits though -depending on beardyness levels.