Okay that will be a scan of your drive. Open your anti virus, check it's updated to the latest version, and look for 'scan' or something similar.Let it scan and check the results.
If it's just running slow you might want to dump the cache and free up some space as well.
WHich AV protection do you have?
If you have an icon for it click on that and there will be an option to run a scan. If there is no icon then look in Programs, open the program and select teh SCAN option