The best defense against viruses is to be prepared and to not get them in the first place. There are a few things that you can regularly do in order to prevent getting viruses.
1. Most Importantly make sure that you have installed on your computer effective virus protection software. The most common ones are McAfee and Norton, which both have an annual fee. They are both very good. A free one is called AVG. If you go to the first link after you search for AVG you will come to the paid version which costs approx. $40/year. Keep looking until you find the actual free version. It is not as powerful as the paid version, but it does what you need it to do.
2. Back up, back up, back up!!! I cannot emphasize this enough. Unless you do not care about anything on your computer and don't mind losing all of it you need to back it up on a regular basis. The frequency of your back ups depends on you. If you use your computer a lot once a week is good. If you just use it now and then maybe once a month is OK. If you have a business and depend on that data daily every day backups are good. There are online programs that you can purchase for around $40 a year that will do a regular back up to a server somewhere (in the cloud). Those servers are also backed up on a regular basis. This type of software is a simple solution.
Another solution is to get a back up drive. There are drives on sale at Office Depot, Staples and many other places. They usually plug in using a USB plug. If you have a Mac you can use Timeline with an external drive to back up your files. If you do not have a Mac you can use any of the back up softwares with a removable drive rather than the cloud. This is so important that if you don't understand what is written here you should find someone to help you.
There are two types of back ups. One is a data back up. This is what most back up software does. It will make a copy of all of your files and data (information saved on the computer), but it doesn't save programs. This type is the most common. Many people keep the original disks from the software they purchase or have paid for them and know that they can download the software again. The other type is an image back up. This is much more extensive and will copy all of the programs on the computer as well as the data/files. If you use a data back up you still need to make sure that you have copies of all of the programs you have added to your computer.
3. NEVER click on a link or an attachment that you are not sure about. There are many negative hackers who can even make your email message look legitimate and put a link into it that opens a virus on your computer. If I get a message with a link from someone I know, I open a new message put in their address (never reply) and ask if they sent it to me. Most likely they did not and will let you know that. If they did send it you can ask them to send it again. People I know would not send a link without explanation and so often without asking I just delete the message.
4. If you are not sure about a link and it looks legitimate you can hover your mouse arrow over the link. Usually in the bottom left corner of your screen you will see the actual URL that your computer will take you to. If you do not recognize the link or it doesn't seem to be related to the sender do NOT click on it. Any legitimate company will send you a link with their company name in it (like www.facebook.com).
IF YOU DO GET A VIRUS ALL IS NOT LOST
You can go to a Geek (look online for computer repair in your area) and ask for help or call the 800 number of your computer maker. If you have backed up your data or have an image of your computer they can help you restore it. If you don't care about what was on your computer before you can reset it back to the way it was when it was new. One big problem with viruses is that they multiply, so it is possible that people in your contact list will get email that looks like it is from you with a link they should not click on. For this reason if you know your computer has a virus immediately take it off the network. For wired computers unplug them from the ethernet cord. For WiFi computers go to the set up and end all of your Internet connections.
Computer viruses are changing and getting stronger all of the time. One recent malware is called Cryptolocker. It will scan a hard drive and then encrypt files so that they can no longer be opened. The only way to get them back is to pay anywhere from $100-$300 to de-encrypt them. That is why it is so important to follow the prevention tips above.
If you do click on something and get a CryptoLocker message or something like that immediatly disconnect from the network. This is one thing you can do to keep from using your contact list to send out other messages that may infect other machines.