Some times malicious programs can infect your registry and fill it with lots of unwanted information. You may need to clean it to prevent the virus from causing any further damage to your computer or to even disable the virus. It is a very lengthy and complex process to do this manually. So you will need to use one of the powerful free tools available online. Hijack This is one of the most powerful program that can be used for this purpose. So go the website and download this free tool. Install the program and run it. There is a new users quick start menu that is shown when you run it for the first time. Select the 'do a system scan only' option from it. This performs a quick scan and presents you with a list of registry entries. You can also save the details to a log. Save the details to a log and go to the hijack this website. Paste the log entries there and the website identifies the malicious entries. Now just fix those entries and clean your PC. This video shows how to clean the registry entries in your PC.