That is what antivirus is for. Free ones work well.
Malwarebytes cleans out some.
COMODO antivirus is free too and has pulled odd stuff out no other antivirus found.
AdAware free antivirus also is good. but has more annoing features than COMODO
The add in the free CCleaner to remove cookies and you got a clean machine
PS i also keep Microsoft Security Essentials going too. Also Free.
