Using this browser instead of Internet Explorer vastly reduces your vulnerability to viruses and ad/spyware. You'll learn it easily, because it looks and functions basically the same way as Internet Explorer.
This program scans your computer for ad/spyware and removes them for you. It might not solve all your problems, but it can often help. Consider running an Ad-Aware scan every couple of weeks as a good first line of defense, to be used in combination with an anti-virus program.