Antivirus software is practically a requirement for anyone using the Windows operating system. While it's true you can avoid computer viruses if you practice safe habits, the truth is that the people who write computer viruses are always looking for new ways to infect machines. There are several different antivirus programs on the market -- some are free and some you have to purchase. Keep in mind that free versions often lack some of the nicer features you'll find in commercial products.
Let's start with the assumption that you're able to run antivirus software -- we'll look into what to do if this isn't the case a little later. Assuming your antivirus software is up to date, it should detect malware on your machine. Most antivirus programs have an alert page that will list each and every virus or other piece of malware it finds. You should write down the names of each malware application your software discovers.
Many antivirus programs will attempt to remove or isolate malware for you. You may have to select an option and confirm that you want the antivirus software to tackle the malware. For most users, this is the best option -- it can be tricky removing malware on your own.
If the antivirus software says it has removed the malware successfully, you should shut down your computer, reboot and run the antivirus software again. This time, if the software comes back with a clean sweep, you're good to go. If the antivirus software finds different malware, you may need to repeat the previous steps. If it finds the same malware as before, you might have to try something else.