What headers are you using?
I'm not familiar with 4.5, but it sounds like you may need to use the Windows way of getting key strokes, instead of the DOS way. MS library has examples of it, but it's nowhere near as easy to work with, imo.
I believe this is right, (from an earlier post on the board):
You need to include windows.h, of course, unless it's already done for you on 4.5
if(GetKeyState(VK_UP) & 0x80)
// up arrow being pressed
// continue looping regardless, without waiting for any input.
MS library has more, check for GetKeyState() or Virtual Keyboard