I have a Dyson Animal vacuum. I am posting this solely so other folks with the same problem can find the solution. The solution was easy once I found it; the problem is that the YouTube video has a title that is too specific to one particular model so my Google searches didn't find this initially. It's a great little video; the guy is a bit hostile and curses a bit much but hey, it's straight and to the point.
Anyone with a Dyson vacuum might find that the vacuum becomes stuck in the upright position. This particular YouTube video is short and sweet and shows the solution. Basically, if you turn the vacuum cleaner upside down, you will see (it's difficult to see) a plastic, black "stick" that holds the vacuum in the upright position. Use a screwdriver to jiggle the latch. Then spray some lubricant (I used silicone spray) so this latch doesn't stick.
"DC28 stuck in upright position FIX"