Those three Quick-Scan option will initiate the loading of a new page that will attempt to scan those areas of your site in one page load. If your server is slow or uses compression or buffering to output the results to your browser then it can sometime take up to a full minute to see any results. I would urge you to to patient after clicking one of those buttons and wait to see if it will complete before leaving the page or trying anything else. If it cannot complete a Quick-Scan in 60 seconds then you should at least see some kind of error message indicating why it does not work on your server.
Even if the Quick-scan feature does not work on your server you should still be able to use the Complete Scan to clean your site. It will take a lot longer but it will be more thorough and complete.
Please let me know if this helps and what results you are able to see after waiting a full minute for the Quick-Scan to finish.