Hitman Pro is a second option malware scanner designed to remove the leftovers of malicious software or files that were not removed/detected during your regular antivirus scan. It uses cloud computing technology and has rather good malware detection ratio, impressively strong against rootkits. Once Hitman Pro detects a suspicious file it uploads the file to the "cloud". The file is then scanned by five antivirus engines: Dr.Web, Ikarus, Emsisoft, Prevx and G Data. These are known names in computer security industry.
Another good thing about this software is that you don't need to install it on your computer. It's a tiny download and fast scan. However, it requires a working Internet connection, otherwise it can’t detect a malicious files and can't upload it to the "cloud" for scanning. It simply won't run behavioural scan. Hitman Pro removes infections for free. Free license is valid for 30 days. Then you will have to buy it which is actually not a big deal because it's rather cheap. However, lack of real-time protection means this product is best used in conjunction with antivirus software.