Have I told you the sad story about the guy who had to pay $2,000 to retrieve the data from his hard drive when it crashed?

How about the one about the grandfather who lost three years of work on his family tree when a pipe broke and flooded the room where his computer was located?

There is no doubt about it. If you own a computer and have any data that can not be easily replaced, you need to have a good backup system in place.

While most people think about backing up financial data and work-related files, they often forget that family photos and accumulations of digital music can be just as important. So backing up should be an urgent priority for all computer users. If you don't have a good backup plan in place, you need to get one as soon as possible.

There are three types of backup solutions:

- File by file backup

- Disk image backup

- Online backup

Your personalized backup system can implement any, or all of the above solutions.

The file by file backup is the most common backup solution. Say, for example, you are a light computer user and find that your important files consist of your Quicken financial data and your family pictures. You can simply back up those important files. Quicken has a built-in backup utility that you can use to back up your files to a CD.

You can also create CDs, which contain a copy of your pictures. This is an easy way to back up just a few files. The only problem is that you have to remember to perform these backups on a regular basis -- something that is easier said than done.

Most users, however, when they really think about it, will find that they have additional important files to back up. There's e-mail, Favorites and/or Bookmarks from Internet browsers, Excel and Word documents, calendars, music, and many other types of digital files.

This is a case where file-by-file backup will still be valuable, but a more comprehensive backup system is needed. One of the easiest ways to handle this situation is to purchase an external hard drive. (Remember that you never want to back up your files to your own hard drive because if the hard drive fails, both your data and your backup will be inaccessible.)

An external hard drive can be easily attached to the computer with a USB cable (or Firewire, if your computer has a Firewire port). The external hard drive can be your dedicated place for backups.

Again, you can pick and choose the files to back up and the frequency of the backup. Better yet, you can institute an automated backup. There are many backup programs available.

One may come with the external hard drive, or you can purchase such a program. Microsoft has a free backup program called SyncToy that will let you set up your backup and automatically keep both the regular and the backup files in sync.

Remember that with a file-by-file backup system, if your hard drive crashes, you will have to reinstall the operating system and reinstall all the programs and then copy all of your files back to the hard drive.

When we speak of backup, we also have to discuss a type of backup called disk image backup. This type of backup takes a snapshot of your hard disk and lets you restore that image. So if your hard drive crashes and you have to purchase a new one, you can restore the disk image and be right back where you started from quite quickly without having to reinstall the operating system or the programs.

Disk imaging software such as Acronis TrueImage and Norton Ghost will help you to both create and restore your disk image. Disk imaging is good in some circumstances. It is great for businesses that need to get back to work quickly, but that works only if you take the disk images on a very regular and very frequent basis.

While a disk image preserves your data, it also preserves any problems, bad files, setup errors and accumulated junk. The best use of a disk image for a home user is when they get a new computer or have just reformatted their computer and reinstalled all the programs.

Taking a disk image of the clean system with the major programs installed will make recovering from a hard drive crash much easier.

Last but not least, if you have a broadband Internet connection, and you are online most of the time, you may want to investigate using an online backup. A good online service will encrypt your files before they leave your computer and will copy them to their web servers.

Whenever you are online, your files will be synchronized in the background, and you never have to worry about backing up your files. Remember that you are trusting the service with your data, so be sure to choose a responsible company. These services charge a yearly fee, but it's a worthwhile investment and a great resource if you want to back up with little worry or fuss.

There are some other problems with backup systems that everyone must think about. What would happen if a criminal stole your computer and your backup files? What if your home or office burnt to the ground or encountered some other physical disaster?

You need to have a copy of your important data off site. An online backup service provides a good off-site backup. The other scenarios do not. So if you want to protect your data completely and you are using CDs or an external backup device such as a hard drive, you will want to make an extra copy of your backup and take it off-site.

You might consider purchasing two external drives and swapping them out weekly, storing the one that is not in use in a safe deposit box, or a different location. Or just make extra copies of those valuable files and take them over to grandma's house for safe keeping.

Don't become a victim of data loss. I have been contacted by a long line of people who can attest to how painful it can be. They have all learned their lesson the hard way, but you don't have to be one of them. Let this article be your impetus to implement a good back up plan.

Sandy Berger welcomes all of your questions and comments on today's column. Please post them on the Compu-Kiss Message Board at www.compu kiss.com/happycomputing.