Windows Defender Offline – At times, users can become exposed to unwanted software or worse malicious attackers. These can potentially compromise your computer by installing Malware, Rootkits and perform other tasks such as having unauthorised access to your system resources. Microsoft provide a couple of mechanisms to either prevent Rootkits from being installed on your computer (Windows 8 SecureBoot) or clean-up your system after an infection with Windows Defender Offline. Follow the instructions carefully and if Windows Defender Offline doesn’t clean up the issue, you may have to re-install your operating system (usually the best thing anyway).