If you suddenly receive more spam messages than you used to or you identify suspicious running applications or processes that you don't remember installing, you probably are the victim of a virus infection.
And if your anti-virus software can't seem to get to the bottom of the problem, you should give this removal tool from Symantec a try, as your computer may be infected with the Trojan.Mebroot. This malware acts as a Trojan horse and modifies the Master Boot Record or MBR, so it can execute its self even before Windows starts
Trojan.Mebroot cleverly hides its presence and opens a back door allowing it to remotely control the compromised computer. Being able to bypass security protocols of your operating system, it will create deep hooks on the core of the OS and will use the back door to download malicious data to your computer and even integrate it in the operating system its self.
What's even worse is that it can install malicious code that will steal private information from the computer and use it to spam your e-mail address or to illicit financial gains.
Trojan.Mebroot Removal Tool detects and permanently removes this threat from your computer. In order to achieve this you have to follow the developer's instructions precisely. Although the application has a basic interface that allows you to start and close the removal tool, if you want to successfully get rid of the infection, there are a few measures you have to take first.
Close all running programs, disconnect the computer from the internet, turn off System Restore (especially on ME and XP) and only then run the program to successfully unhook the virus from your system. After removing the trojan the app requests a computer restart and after that, to make sure you got rid of the threat, run the application again.
If you were infected with Trojan.Mebroot this should be more than enough. it is specially created to target this threat. When you are done, don't forget to restart the System Restore and restore the Internet connection.