In this day and age, computer viruses are a fact of life. They are also capable of causing significant damage to your computer or even your entire network. In order to minimize the chance of your system's security being compromised, here are some helpful tips.
Windows Security Center
Make sure that you enable all the features of the Microsoft Windows Security Center, and be sure to update windows whenever prompted (you will need a genuine copy of a Windows operating system to do this). If you are unsure how to go about this, visit Microsoft's Protect Your PC site and you can find detailed information.
Install an antivirus program. There are several effective free antivirus programs such as Avast! and AVG that you can use on your home computer. However, for the greatest amount of protection (and for work PCs), you'll need to upgrade to a paid antivirus subscription from a company like Norton. Avast! and AVG also offer enhanced subscription services.
Secure Your Network
If your computer is connected to a wireless network, be sure to secure the network with an encrypted password. If you leave your network open, anyone within signal range can access your network, and potentially access all of the computers that are connected to the network.
Be Careful What You Download
The most common way Viruses are transmitted is through voluntary user download. Often times, viruses are disguised as applications or other files attached to emails or available for download on suspicious websites. Many email providers now offer built in virus scanners that will scan attachments before allowing you to download them, but they are not foolproof. Always make sure you know who the email is coming from that contains the attachment before you download. Never download anything from a website that you do not trust or that you do not feel 100% safe about.
Don't Use Bootlegs
Aside from the legal consequences, using bootlegged CDs to install software can also make your PC vulnerable to attack. Many times bootlegs are distributed with viruses (or they are just viruses, altogether). If you don't know or trust the source of the CD, don't use it.
Free Programs Aren't Always "Free"
Back Up Your Data Frequently
One of the most devastating consequences of a computer virus can be the corruption of data. Some viruses simply erase data. The only way to fully safeguard against this is to routinely make full backups of your entire system. If you simply have too much information on your computer for this to be a reasonable routine, then at least make a habit out of regularly backing up the data that is most important to you (personal messages, records, photos, etc). A standard, single layer recordable DVD holds 4.3gb of data, which depending on the amount of information on your computer, may or may not be enough to backup your most sensitive data. If not, you can use multiple DVDs to store data. New, high definition DVDs can hold up to 50gb of data. If you don't have a DVD burner, you can also use separate, external hard drives to backup data. There are also USB compatible flash drives that are very portable, and some can hold several gigabytes of data.