can someone help me with DOS?

[sonickteam2]

i got this old computer game that runs on DOS. and i can play it but its wicked fast on my computer, so i downloaded this thing called DOSbox. but when i go into DOSbox, i cannnot open the .com file.  i dont understand.  i can see it in the dir but when i type the name or run or anything i am stuck at the C:\> prompt.....
 
 help? anyone?

[sonickteam2]

nevermind, i fingered it out, but another question arises.....when i maximize my DOS window, its not centered, so i cant see the whole screen....how can i center it?