This is a list of things to do if you have an active infection. It can be hard to download when your computer is under attack so I recommend getting them ready for the sad day you need them, just remember to get the latest versions at that time if you can.
It's not always easy to tell if your computer has been infected with malware. If it is unusually slow, crashes or stops responding frequently, for example, these problems might be signs that your computer has been infected.
Most people have heard of computer viruses but rootkits are less well known. Rootkits are just as undesirable but usually don't cause automated damage. They are programs that give someone else "administrator" level access to your machine without you knowing it.