You need an anti-virus program on all your computers (laptops, desktop, tablets, etc) and smart phones.
The anti-virus program will do two things. It will remove viruses from your device that are already there. Most anti-virus programs will do a second item and that is to act as a vaccine and prevent viruses getting on your device.
You will need to run updates on the anti-virus program regularly to get new definitions and program updates. The definitions include how the program knows something is a virus. New versions of anti-virus programs come out usually annually and you need to get new ones as they appear. I have seen machines that people said had an anti-virus program that was 4 or 5 years old. They were right that it did have a program, but the program was basically worthless as it knew nothing about viruses developed in last 4 or 5 years.
Avast is a good free anti-virus program that I use. AVG is also good. and free. I like Norton but once in a while they get a bad program and also it is not free.
Spyware is different than viruses. Most anti-virus programs claim to protect against spyware, but I have found them marginally effective in this. I suggest getting a anti-spyware program to use also. Superantispyware at superantispyware.com is one I like best and is free.