Send password to application

I'm looking for soultion for like sendkeys in VisualBasic.
After install one of elements in install sections I'm running application and after few seconds I want to send Password and press Enter.
I found Handle of prompt window but I don't know how to send password to it.

Can you help me?
K_W

DOS or Win application?
SendMessage WM_SETTEXT for Win apps (NSIS Manual 4.9.14.9), ExecDos plug-in for DOS http://forums.winamp.com/showthread....hlight=ExecDos