Not unless you reinstall your OS from known, clean media on a regular basis.
Malware scanners and anti-virus software only help you after you get infected and only if the software can detect the malware. Malware writers have become exceedingly good at evading detection.
Report: 48% of 22 million scanned computers infected with malware
That's half. One out of two. So here's the experiment:
Ask the person next to you if they are infected with malware. If they say no, then it's you.
Ask yourself if you've been using computers and designing software since the early 1980s. If the answer is "no" then it's somebody else...