For more experienced users, Pro-ActiveComputing can introduce you to some other measures that can greatly assist you in protecting your computer and network:
Sandboxing - Sandboxing allows you to browse the Internet or view your email with little or no danger from malicisious software. The software allows you to create a virtual "sandbox" for you to run your applications in. When you have completed your online session, you simply empty the sandbox. Anything that was installed on your computer goes away with the sandbox thereby protecting you from any software that you installed either knowingly or not.
Virtual machines - Virtual software allows you to create more copies of your operating system and run them in a "Virtual Mode". Similar to sandboxing above, this protects your real computer from any bad items that happen to get loaded onto your computer. Virtual software allows you to do more than sandboxing because you have a fully loaded virtual computer and can pretty much do anything you can do with your real computer. When you are finished you can just reload a new Virtual operating system and start over. You also have the flexability of running different operating systems on your computer for testing or just learning something new without impacting your real computer.
Linux - Linux is an operating system similar to Unix. It is far more secure than Windows and can be used for many of the same tasks you do with Windows today. I like to use it for secure web browsing when I do banking or Credit Card tasks and checking email because I know it is much safer. It does not require the resources that Windows does so it can run great on older computers. Some versions of Linux also allow you to run directly from a CD which prevents any software or viruses from loading on to your hard drive.
Network Segmentation - Network Segmentation means running more than one network segment which allows you to segment your computer tasks relating to the level of risk. With a segmented network, you can do your high risk computer tasks on one network (opening email attachments, downloading music, testing new software etc.), and your low risk and secure tasks on another network (Banking, Credit Card transactions, etc. This prevents your high risk computer needs from currupting your secure tasks such as banking. If you are using only one computer and network then you are at high risk of having your bank accounts or credit card accounts raided.