PITTSBURGH — No matter how good you get at computing, there will be humbling moments. A screen freezes, a hard disk crashes, the sound card goes mute. We have stressed throughout this series the importance of getting a computer buddy. A knowledgeable user will be most valuable during such crises. Still, there can come a time when your buddy is stumped - or so swamped with his own work, he can't focus on your problem. That's when you need outside help. Here are some rules to live by: * Don't panic. The worst thing that can happen is that you lose all your data. This may seem like a cruel blow, but if you have been following the advice in this series, then you have taken steps to minimize your losses. Meanwhile, all your software programs are safe (since you have the original floppy disks). * When something really awful happens to my system, I use a hierarchy of keystrokes to get out of the jam. First, I hit the ''Escape'' key a few times. If that doesn't solve it, then I try a combination Alt-Tab to toggle to another screen in Windows (Command-Tab for the Mac). If I'm still stuck, I try Control-Alt-Delete to shut down the offending program (Command-Option-Escape on the Mac). If that doesn't work, I restart the computer with another Control-Alt-Delete (or Command-Option-Power Key on the Mac). If I'm still stuck, I hit the ''Reset'' button on the CPU itself or turn the machine completely off. I may lose hours of work, but the actions won't harm the machine. * Keep losses to a minimum by saving your work often. I usually forget to do this on my own. Fortunately, many software packages will do it automatically, every 15 minutes (or whatever interval you set). * Make sure you have access to rescue disks. Normally, they come as part of utilities software programs. Even if the machine won't restart on its own, these disks can almost always get the system started so you can take appropriate action from there. If there is one piece of advice you take away from this series, besides getting a computer buddy, it's this: Get utilities software. If disaster strikes, you'll be glad you did. * You'll be even happier if you keep backup copies of your most important files. If there are just a few files, you can easily copy them onto floppy disks. If you're keeping important business records on the machine, get backup software and either a tape backup or a removable hard-drive system. Getting help for a disaster is one thing. Finding answers to everyday questions that stump your computer buddy is a little trickier. Help is out there, but you'll have to learn new skills. Mostly, this is because computer technology moves so fast. Books that cover a particular piece of software have a short shelf life before a new version of the program makes the book obsolete. General books on operating a PC hardly exist because they're outdated even faster. This makes it particularly difficult for the novice. Special magazines are better at keeping readers current with a particular piece of software, but they cater to specialists, not novices. You can go to computer dealers who may - or may not - know what they're talking about. ''I always tell people not to be overly influenced by things that they hear, or by sales people when they walk into a store,'' says Ron Kobler, editor in chief of PC Novice, published in Lincoln, Neb. ''When you don't know the terminology, it's very easy to be swayed by a person in authority like a salesman. Try to read up a little bit on computers before you go to the store.'' PC Novice, which comes out monthly, is one place to turn for answers. It has a section devoted to the beginning user. Surprisingly, its average reader has owned a computer for six years. Its focus has broadened to include a more general audience. Some experts sing the praises of Usenet as a source of help. It's a part of the Internet where people gather in groups to discuss a particular subject. The leaders of such discussion groups are well-intentioned, but they speak a different language than the beginner does. Last spring, a Thai user posted a basic question to a DOS user group: ''Does anybody please explain to me about DOS error message Sharing Violation?''' He got two responses. ''Actually, SHARE is an executable, not a device driver,'' one member wrote back, ''so it should be loaded in the autoexec.bat* (or with INSTALL=C:\SHARE.EXE in config.sys*).'' The other response was also full of computer-speak. Even if that Thai user managed to understand the English, I doubt he got the answer he needed. Better forums are available from on-line services, particularly CompuServe, which hosts hundreds of software- and hardware-specific discussion groups. But beware the language barrier. People who understand computers often speak like one. As an antidote, try a local computer club. ''The main theme here is users helping users,'' says Tom Heffernan, president of the Association of Personal Computer User Groups in Washington. This umbrella group lists 2,000 user groups around the country. But Mr. Heffernan estimates there are three times that number. If the association's automated locator service, (914) 876-6678, can't find a local computer club, ask a computer dealer in town. Many user groups include classes or get-togethers for beginners. Many also hand out telephone numbers of members who have become experts in certain areas or specific software. As a club member, you're invited to call and ask them questions. If they use computer-speak, don't be embarrassed to tell them you've never heard of an ''autoexec.bat.'' That ought to get them to simplify their explanations in a hurry. Another possibility: Community colleges often offer inexpensive computer classes. Make sure that you really want to learn what they're teaching. Eventually, you'll get over your PC reservations and become a dedicated user. Some new users go too far: One day they're novices, the next day they're talking endlessly about the latest PC model and when the next version of their favorite software will be shipped. They move in lock-step with an industry that's setting a frenzied pace. Avoid that, if possible. Computers are a valuable tool, but they're not the answer to every question. Early in my computer career, I decided to automate envelope addressing. This worked all right when I was sending bunches of letters. If I had just one, I found it far faster to write out the address than to turn on the printer, insert a label, and print it out. My latest purchase in address technology? A $15 self-inking stamp for my return address. You get the idea. We're all riding an immense wave that rivals the previous technological crests that have crashed on our shores: the telephone, the automobile, the booster rocket, and so on. Perhaps this PC wave exceeds those others. It certainly seems to be traveling faster. And the people perched on top all cry: Hurry up or get left behind! Don't believe them. You're learning a lifelong skill. You don't need to rush. * Last of a series. Parts 1, 2, 3, and 4 appeared Aug. 22, 24, 25, and 28.