The battle against trojans and spyware is a constantly ongoing one but there's no need to spend big money on expensive solutions.

a-Squared is a free anti-spyware/anti-malware scanner that can pick up just about anything that's illegally installed itself on your system. It frees your PC from malware after a simple and fairly quick scan to improve your PC performance and reduce any performance or internet related problems. However, this is one program that does so with caution which is a refreshing change. Instead of just wiping anything off your system, it places those components that are critical to system performance in quarantine meaning that there is less chance of your system becoming unstable after a scan. The program is regularly updated although unfortunately not automatically - you have to instruct it to perform an online update at periodic intervals. The program has clearly been designed with beginners in mind - there are no complicated scanning functions or strange components to deal with. It reminds me somewhat of CCleaner and in a way, performs a similar job but with a focus on malware instead of temporary files.

An extremely simple and affective malware scanner, it should pick up any illegal software that's attached it self onto your system in a safe and secure way.