dont know where to begin to find old dos game???

[bitshifter]

i am looking for an old dos based game, late 80's early 90's, It is a 2d side scrolling game where you are a red robot kind of like a transformer and you had to make your way to the right (and the screen would scroll right) to reveal enemy robots (i think) that were trying to impede you. but you could transform into a plane (also red), once you were in plane mode you couldnt stop. you either had to go left or right, up or down to navigate around walls and obstacles. you could change back to robot whenever. any help would be appreciated.

[Tequila]

Look at http://dosbox.sourceforge.net

[Commander Keen]

The name is Thexder

http://www.mobygames.com/game/shots/p,2/gameId,49/