I've been playing around with software that's supposed to diagnose and help you solve hardware and software problems. And, although none really did a thorough job, I found one that came close.

Universal Diagnostics 2000 from Micro 2000 contains a complete diagnostic tool kit, including Micro-Scope software, loopback plugs for serial and parallel ports and micro-channel and PCI Post Probe cards that test your motherboard.Obviously, this is not for those that cringe at the thought of delving into a computer's innards. But for the rest of us, this may be as close as we can get to computer Nirvana.

Here's how it works.

First you boot up your system using the Micro-Scope disk. After a few whirs and buzzes, the disk will start to analyze your hard drive, diagnose and fix bad sectors and correct settings that may have been configured incorrectly when the drive was installed. Sometimes it even revives drives that have been left for dead and have become expensive paperweights.

It will then ask you what tests you want to perform. This is where the loopback plugs come into play.

If you select ''run all tests,'' it will diagnose your motherboard, cache memory, base memory, extended and/or expanded memory, floppy disks, hard disk, CD-ROM drive, sound card, serial, parallel, SCSI, and your video card. The loopback plugs must be attached to the serial and parallel ports on your computer before they can be tested, and a CD and floppy disk must be inserted in the respective drives before tests can be run on them.

Once all this is completed you are given a pretty accurate picture of how well your system is operating and are advised on how to correct any problems.

The Post-Probe cards are intended to diagnose problems with your CPU and motherboard, especially if your computer won't boot up. The card must be inserted in a vacant PCI slot on your motherboard. Then, once the computer is turned on, the card will begin to analyze everything from system memory to your video card. It uses post codes to diagnose problems and will flash numbers on an LED display indicating where the problem is.

The numbers also show you voltages, bus signal status and what is known as the reset line.

Obviously, you should know quite a bit about computers before using this card. But, if you're computer savvy, you'll be given a good idea of where the problem lies and should be able to fix it. For those of us who are less computer literate, Micro 2000 also publishes a Basic PC Learning Course, which comes with MicroScope and walks you through all of the features of your PC.

Now, if you have no desire to delve into the inner workings of your computer, you can try System Suite 2000 from Ontrack Data International. This is a complete set of diagnostic utilities that will test your video card, sound card, hard drive, CD-ROM drive, floppy drive, system memory and other doodads plus check for bad drivers in Windows.

While it didn't find as much as the Toolkit, it was pretty accurate in detecting problems with my system and recommended ways they could be fixed, similar to other programs of this type.

But be careful when implementing recommended changes. As with other types of diagnostic software, selecting ''fix all problems'' could render your computer useless and you'll have to go through the tedious task of reformatting your hard drive and reinstalling all your software.

I've found this to be particularly true when using Symantec's Norton SystemWorks 2000 and First Aid from Network Associates.