I have been using Spybot Search & Destroy for a long time, and each scan would normally detect and remove a piece of malware. However, I had a feeling that not all was being removed. This was confirmed when running Spyware Detector (as recommended in a major PC magazine) which detected and removed a large range of keystroke capture software and adware. Since Spybot was unable to detect all the malware on the computer this makes me concerned that Spyware Detector may also not detect all such threats, and some may remain undetected on the computer. Since I do internet banking on the computer I want to ensure that my details remain safe. Do I have cause for concern?

You have raised some good points of concern in your question. The first relates to the effectiveness of anti-spyware and anti-adware software. I am a strong believer that you cannot rely on one piece of software, such as Spybot or any other single program, to satisfy all your spyware and malware scanning requirements. Whenever I advise users to scan their computers I strongly recommend that you use a combination of scanners, mainly Spybot Search & Destroy (www.safer-networking.org), Ad-Aware Free (www.lavasoft.de), and Windows Defender (www.microsoft.com/downloads). Using a combination of scanners provides you with the best opportunity to detect and remove any malware which may be installed on your system. However, you cannot be absolutely certain that these utilities will be able to detect and remove all malware which may be present on your computer. In fact, the general rule of thumb is that once your computer has been compromised with malware you can never trust the computer again, as it is possible that remnants of the malware have remained behind. In your case, since you were using internet banking while your computer still had malware installed (particularly, keystroke loggers) this could mean that your computer and passwords have been badly compromised. In this case, I strongly recommend that you change any internet banking and other sensitive passwords. Additionally, since you cannot trust your computer system anymore, I suggest that you backup any data you wish to keep on the computer and then do a reformat and reinstallation of Windows. That is the only way you will know for sure that the integrity of your system has been restored and it can be trusted again. Obviously you will only want to change your passwords after you have reformatted and reinstalled, otherwise you may be changing these passwords on an already compromised computer.