You may consider using Autoit which is more reliable than SendKeys.
Download Autoit from below link
http://www.autoitscript.com/site/autoit/downloads/
Add in reference autoit addin
AutoItX3 1.0 Type Library
Below is sample code which will open the calculator and type 123456789
Sub sendkeys()
'Open a calc
StartCalculator
Dim au As New AutoItX3Lib.AutoItX3
au.AutoItSetOption "WinTitleMatchMode", 2
au.WinActivate "Calculator"
'send key strokes
au.ControlClick "Calculator", "", "Button5"
au.ControlClick "Calculator", "", "Button11"
au.ControlClick "Calculator", "", "Button16"
au.ControlClick "Calculator", "", "Button4"
au.ControlClick "Calculator", "", "Button10"
au.ControlClick "Calculator", "", "Button15"
au.ControlClick "Calculator", "", "Button3"
au.ControlClick "Calculator", "", "Button9"
au.ControlClick "Calculator", "", "Button14"
End Sub
Sub StartCalculator()
Dim Program As String
Dim TaskID As Double
On Error Resume Next
Program = "calc.exe"
TaskID = Shell(Program, 1)
If Err <> 0 Then
MsgBox "Can't start " & Program
End If
End Sub
