using the api
Private Declare Function SendMessage Lib "user32" Alias "SendMessageA" (ByVal hWnd As Long, ByVal wMsg As Long, ByVal wParam As Long, ByVal lParam As String)

what do the wParam and lParam do? what kinda stuff is specified in there...

and also how would i use sendmessage to send keydown event....

heres what i got...
Private Const WM_KEYDOWN = &H100

SendMessage apphwnd, WM_KEYDOWN, 0, 0

but what and where do i put if i want to call lets say H, E, L, L, O keys?