I finally got a laptop (whoo!). I just got DOSBox onto it and I've been having a problem with color in full screen. When I use it in a window the color is fine, but when I switch to full screen, the color is usually right for a second and then "twitches" to the wrong colors. Sometimes the colors are fine but change when their area of the screen changes, i. e. something else is displayed. I found this problem with the old QBASIC program, so (I think) I know what's happening: the colors are getting swapped, red <--> blue, bright white <--> brown, bright blue <--> bright red, and most of them, which means this is a good place to mention I've only seen this in 16 color mode. I don't have any compiled games to test it with, but I have Nibbles II (fan game) for QBASIC (a variation on the old game where you eat numbers and get longer) and the problem showed up in the interpreter and the game. I've had this problem with our desktop too, but not as much. It seems there's some way (or two) to make it stop, but it rarely works twice in a row.
The laptop is a Compaq Presario running Vista (I know, but I didn't have a choice) at 1.8 GHz with a ~80 GB HDD and I think it's at 1280 x 960.