if it was mine i would download the free additions of

adblock plus ( for whichever browser you use

then download the free editions of malwearbytes and superantispywear and run them in that order

also the free edition of cc cleaner and run that ( also run the registery cleaner part as well)

disc cleanup and defrag after would help

probable take you most of a day but you will then have a computer free of spam and malwear and will run a lot faster