Trend Micro's Fake Antivirus Removal Tool is a specialised anti-malware utility that will detect and remove many of the most common scareware threats.
You'll have seen these in action on many websites, popping up windows with fake antivirus scans and claiming that you've been infected by something. If you just close those windows right away then you're probably safe. If you allow them to trick you into downloading their executable, though, you'll get more warnings of deadly infections, along with demands that you purchase their bogus products to clear things up: and that's when you need Trend Micro's Fake Antivirus Removal Tool.
The program can be surprisingly quick and easy to use, because it scans running processes rather than files. And so all you need to do is click the Scan All Processes button, and wait for its verdict. (Or you can even opt to scan particular processes if you know where the threat is already.) In just a few moments any fake antivirus tools on your system will be disabled, and your PC should be back to normal.
Please note, the Fake Antivirus Removal Tool has an executable file name of svchost.exe. The idea is that, if your particular infection is blocking executable files, then this one will be allowed to run as it has the name of a system component. However, it's also possible that other security programs may raise alerts about it as this copy of svchost.exe won't be in its usual place, so be prepared.