Software viruses are basically small programs, usually with an EXE (executable) or VBS (Visual Basic Script) extension, that trick your computer into destroying or altering files. There are many kinds of viruses: worms, logic bombs, Trojan horses, etc.; the names don't really matter. Most of them are minor nuisances, but a rare few can destroy your files or cripple your computer.
Where do they come from? They seem to be mostly created by immature males with personality problems. Programming skill was once required to create viruses, but now there are Internet sites where prefabricated ones are available to anyone who wants them.
How do they get on your computer? Viruses depend on stealth and camouflage, so they're normally hidden inside innocent-looking files that you load onto your machine. In the early days of computing, viruses were sometimes found on commercial software, planted there by disgruntled employees (that's still possible, but uncommon now.) Sometimes they're hidden inside free games on the Internet or other tempting goodies. Most often now they're in an email attachments. Because Microsoft Windows, Outlook, and Word are installed on more computers in the world than any other software, most viruses are designed to attack them, but any software is a possible target.
If you use Word, turn on the macro-warning feature and don't open a Word file with active macros unless you know who made them. When in doubt, choose the "disable macros" option before opening the file. If you use Outlook email, turn off the preview pane feature. If you use Windows, never open an unexpected email attachment. Even if it appears to be from someone you trust, double-check with them before you open it. Viruses can take over a victim's address book and send copies of themselves to all their friends.
The best overall defense against viruses is to subscribe to one of the commercial antivirus services such as Norton ( http://www.symantec.com/nav/) or McAfee (http://www.mcafee.com/). For a small annual fee, they give you software that searches your computer for any viruses already there and checks all new files that you open. Be sure to download the regular updates they provide. Software viruses mutate even faster than real viruses and you don't want to depend on out-of-date protection. Both companies also post lists of all known viruses and virus hoaxes. If you if receive an email from a friend warning you about some new virus, please check the professional sites before you pass the warning on since the vast majority of such warnings are hoaxes.
Viruses aren't the only threat to your files. Sooner or later, your hard drive will die. It's not a matter of if, it's a matter of when. If you have files that you can't replace, like the book that you've been working on for five years, you need to make backups.
Maybe you already do backups, that is, make copies of your files onto a diskette. That's fine, but consider what would happen to your copies in case of flood, fire, tornado, or burglars. If something bad happens to your computer, the same thing could happen to a backup that's in the same room as the computer.
What to do? Keep your copies elsewhere, preferably miles away, in another part of town. Your writing buddy next door may be willing to store a couple of diskettes for you, but the tornado that hits your house may hit hers too. Whether they're stored at work or with a friend, put some distance between your backups and your computer. Diskettes are cheap and making copies of text files is fairly fast. You'll probably never need the copies, but, if you do, it'll be well worth this small effort.
What files should you back up? The ones that can't be replaced. You can always reinstall or buy new software; it's your original work that needs protection. How often should you make copies? Depends on how much work you're willing to risk. If you just spent eight hours on something, is it worth five minutes of extra effort to back it up? It would be for me, but, hey, I'm a worrier. Find your own level of paranoia and act accordingly.
There's a lot of wasted "space" in most text files, and applications like WinZip ( http://www.winzip.com/) or PKZIP (http://www.asizip.com/products/products.htm ) can tidy up by creating ZIP (compressed) files, sometimes packing a document down to as much as one-tenth of it's original size. If you're backing up your text files onto floppy diskettes, you may find such a compression tool very useful.