Comodores, Ataris, and early AT's ran on ANSI graphics. This meant 16 colors (if you even had a color monitor) as those were by far more expensive than they are now. The first color monitor I bought was $400 which would be nearly $1000 in todays money. And alot BBS's were not in color anyway. They did not have internet then, it was just getting started.
To get around the color issue, most would hook up to a TV set. There was no real call for a color monitor unless you had VGA graphics with 256 colors, and this was not common until until the vary late 80's or early 90's. Then a photo would actually look something like a photo, rather than a cartoon.
Until the internet got off and running people would dial into a BBS with a phone modem at 300 baud. When the speed finally got up to 14.4 it was a big leap, because now the print actually appeared on your screen nearly as fast as you could read it. Imagine having to wait for each word to appear on your screen one by one, how frustrating that must have been. Yet we were having fun, we thought it was a miracle.
Early BBS was one user at a time. You would sign on, write something, and then get off so someone else would write something.
The first PC's, many of them, did not have a hard drive. The operating system ran on system memory, all 640 or 128k of it. A floppy would only hold 300k, but was actually enough to run several Arcade style games, or a pretty sophisticated word editor. I say sophisticated because you could do alot more with it that than with an IBM Selectric, and that was great news. Hook this up to a dot matrix printer which was so noisy you could not use it and talk on the phone at the same time, and you could really increase your productivity. But you were still limited to only one font.
The mouse and GUI were no where to be seen. This, and the internet in large part were not around until about 1993. Until then computing was all DOS commands. You would play a game using the arrow buttons, etc
To boot up your computer would take around 4 minutes. Faster, if you had a hard drive, then maybe only two minutes. The typical hard drive was 20 or 30mb and cost around $300, so many folks did not have one. $300 then would be over $600 today.
Generally speaking it was an expensive hobby that really did not do very much. If I had to pick out one thing that stands in my mind, it was that you only had one font. But another thing that sticks in my head was that back then people would write a program in about 50k what and nowadays a similar program takes up to 50meg.
And some of the Arcade games were actually quite good, considering. There is still a bit of a nostalgic fan club for the early Atari games. Also, people who used to run some of the early BBS boards are still well remembered
Edit. I just remembered that no discussion of this would be complete without mentioning OS/2, link below