It's been 17 months since a personal computer was first cranked up in our house, and just a tad more than a year since I began writing this column. Seems to me that it's about time for a little recap on what's been learned.

How 'bout just a few hard-won tips on how to go about buying a computer?

Here they are:

1. Figure out what you want it for. Is it for fun and education? Then look at the lower end of the price range--you may decide that computering is not for you, so it's best to keep your initial investment low. There are plenty of good buys in the $50 to $500 range.

On the other hand, if you're looking for something to help you run your business, you're going to need a sophisticated keyboard and a lot more memory--at least 48K worth. That means a minimum of $2,000..

Those advertised packages of businessmen's specials? They're just the beginning. They usually don't include a printer or a telephone modem or anywhere near all the software you're going to need.

Unless you're rich and can afford a big mistake, be prepared to do a lot of homework. The market's vast and confusing.

If the computer is to serve as both a game arcade and a business tool, you're going to end up spending $1,000 to $2,000. This is the meat of the market, and the selection is the best.

2. You should feel comfortable with the computer keyboard. So try out every machine in the store. But after that, the most important thing to remember is: The key to a successful relationship with a computer is its software.

Good software can make any computer great. Is there more software available for one of the machines that interest you than for the others? If so, you ought to let that weigh heavily in your purchase decision.

If there's a lot of software available, you'll be able to expand your machine's usefulness that much easier plus have a better shot at finding a program that suits your original needs if what you started out with didn't work.

3. Read one of the good computer magazines like Popular Computing. Not only do they write about the nuts and bolts of computing in language that neophytes can understand, but they also contain mail-order advertising that gives you an idea of the bottom price on things you may end up buying.

But be cautious about ordering through the mails. If something goes wrong, it's sometimes worth the extra dollars you spent buying it locally just to know you can go pound on a door rather than have to scream over a transcontinental phone hookup.

4. When you narrow your selection down to one personal computer, find out if there's a user's group in your area for it before you buy. Just ask the computer sales personnel. They should know. If they don't, they aren't doing their homework, and that's something to take into consideration.

Attend one of the meetings. Talk to the people who are members. While they're usually enthusiastic about what they own, they can warn you about pitfalls.

Even more important, they know where the best and cheapest place is to buy your computer and software. Often they make group purchases of hardware and software that can result in even greater savings. And they'll be a great source of help if you have problems with the machine after you buy it.

5. Remember that chances are your homeowners insurance policy does not cover your new computer. Check with your insurer. An upgrade doesn't cost that much, and home-computer theft is increasing.

6. Prices are plunging in the computer industry (what a refreshing experience!) so there are good used-computer buys. But have key parts, like disk drives, checked out professionally before you agree to purchase.