What should I do if my PC is infected with a virus?
You cannot remove a virus by installing anti-virus software; you must remove the virus first. There are various tools which will scan your computer and detect and remove viruses for you.
You need to do this whilst your PC is in safe mode. To do this, start up your PC and repeatedly press the F8 key. Select safe mode from the list of options which appear. Once your PC has booted up you can run the following software to try and detect and remove any infections: