As computers get more reliable, backup of your hard drive may not seem a major need. Wrong, then you may not, as yet had a major crash.
If you haven't then you are very lucky but when it does; you'll wish that you had backed up your hard drive, that added to the virus problems, when you pick something up that is very nasty.
There are a lot of programs for backing up out there but Ghost 10 is one that I use and have for a while, it very reliable and easy to use the only other thing you need is an extra hard drive, which these days can be picked up for a few pounds. An internal drive is the best as it's faster than a USB external its also cheaper and can be fitted by almost anyone, as no great knowledge is required just common sense and a read of the instructions or check out the instructions on Google (how to install a hard drive)
There are 2 ways to back up, the first is saving files so if you lose a data file, then it will be on the back up-drive therefore individual files can be uploaded to your main drive usually C: The programme that I use, is a mirror back up system, which saves a whole copy of your drive to your extra hard drive so if your hard drive does have a major crash or you accidentally download a virus or a program that causes problems, then you can upload the whole mirror image of your hard drive, as it was before the problem arrived (this has saved me many times) it over writes the hard drive and then re-writes the data to the drive, so now your old hard drive is as good as new.
If you partition (divide the disk space into sections using a program like partition magic) your extra drive then (depending on size) one partition could hold the file copy another partition, the mirror copy. Another good thing about the mirror copy is, if your hard drive dies then the new drive can be installed and a copy of the old drive can be installed on the new drive.
Finally this is very important, your hard drive must be backed up on a very regular basis, if you don't then you will not have an up to date copy to upload, this is very easy to do. The program comes with a very comprehensive instruction manual, which gives you a lot of other things that it can do but far too much to go into here.Norton Ghost costs between £10 to £20 from Ebay or Amazon.