As far as I know, the 600x is the most modern laptop that still has drivers for win 3.1 and DOS 6.22. I like DOS 6.22 cause some of my favorite old programs don't like and version of windows, and dos 6.22 can be run without windows. Most DOS based programs have options for sound or no sound, and they lock up if I select the sound option. I also have 560x and a 600 and neither have this problem. I would prefere to use the 600x because it can do things a 560x and 600 can't do. On the same 600x I also run win M. E. and win2000, each in a seperate patition using partition magic, and also on the 560x and the 600. This sound problem seems to be peculiar to the 600x. Hope someone has a solution.