Life was once so much simpler for users of the IBM Personal Computer and compatibles. All they had to decide was which kind of spreadsheet or word-processing program they wanted. To run those programs and other operations of the computer, they had no choice but to use Microsoft's MS-DOS operating system software.

These days, things aren't so simple. To decide what kind of operating system software to use, you have to understand things like Windows 2.0, OS-2, the Mach 20, LIM boards, MS-DOS 2.11 and MS-DOS 3.3. All of this confusion comes from the authors of MS-DOS -- Microsoft of Redmond, Wash.

As if we weren't all confused enough, Microsoft is promising yet another piece of operating system software, called Windows 386. Windows 386 will allow users who own a PC compatible based on the Intel 80386 chip to load more than one program at a time and switch among those programs. Windows 386 also will offer sophisticated software techniques to let those programs work together.

But Windows 386 raises a lot of questions because Microsoft has announced several other products that will achieve roughly the same thing.

Operating system software tells your computer how to deal with word processing programs, spreadsheets and other so-called application software. Microsoft started out with MS-DOS and has upgraded it over the years. The most current version is 3.3, although most people I know are still using version 2.11.

About four years ago, Microsoft decided that MS-DOS wasn't good enough. It announced a program called Windows to make MS-DOS work more like Apple computers, with pop-up menus and windows on the screen. Two years later, Microsoft finally delivered the first Windows.

Real confusion started in April when IBM replaced its PCs with the Personal System-2 line of computers. On the same day, Microsoft and IBM announced they would develop a new operating system called OS-2.

The new system, expected around August 1988, would run on IBM computers and other computers that use Intel 80286 and 80386 chips.

But at the same time, Microsoft announced a Windows upgrade called Windows 2.0. The program, which is supposed to be available by the end of this month, will run on a regular PC or more powerful computer, Microsoft said.

As of last Wednesday, when Microsoft announced Windows 386, the company had two versions of Windows announced and possibly available, at least two versions of MS-DOS in use and a phantom called OS-2 that is supposed to be better than all the other systems.

It's safe to say that when it comes to operating systems, PC users are in a state of total chaos. They face myriad questions, including:

Should owners of 80286 computers use Windows 2.0, DOS 3.3, DOS 2.11 or wait for OS-2?

Should owners of 80386 computers use Windows 386 if OS-2 is coming out in less than a year (if it really is)?

If Windows 2.0 really runs on a standard PC with an 8088 or 8086 chip, why is Microsoft offering the Mach 20 board to let PCs use both OS-2 and Windows 2.0? The Mach 20 board adds an 80286 chip to a PC compatible for $495 to $989.

What operating system should people use if they buy a Lotus-Intel-Microsoft Expanded Memory Specification board to make their PC compatibles use more than 640K of memory?

Let's hope we get some answers from Microsoft before we get more questions.endqua