Prevention is ALWAYS better than the cure when it comes to dealing with virus or malware infections, but we can help and there are several approaches we can take before resorting to an Operating System re-installation.
The only guaranteed way of removing a virus infection is to re-install the operating system. This is a belt and braces approach, a last resort and does require re-installation of all your applications, but it is important to realise that it may be your only option.
Has your computer slowed down recently?
Do strange Websites pop up now and again?
Has your home page changed by itself?
Have strange icons appeared on your desktop?
All of the above are signs that your computer might be infected, but it is by no means exhaustive. If you are worried please get in touch, the sooner your report the problem the less chance of damage to your data.