Although the applications mentioned in Vishal Bakhai's post are extremely good and highly recommended, I would like to offer a different approach. Sometimes even if you use antimalware applications or antivirus solutions, there may be leftovers. It means that there could be additional threats hidden in the kernel level of your OS.
To prevent it and scan at a deeper level, you can use GMER. This application scans the services up to Kernel level, meaning that it detects the files that tampered with your OS. Download and install the application and perform a search. If you find any items in red, right click each one of them and select Delete. This way you know that the malware has been deleted completely.