Here's the thing. Do you have any other controls on the form which accept keypresses? Like a combo or text box. And if so, if they have the focus when you press they will receive the #1 too. But you know that.
To remove that possibility, reset the key to 0 if pressed. This way nothing happens. This will unfortunately remove your ability to type the number 1 into the text box. You could get around that if need be.
Code:
Private Sub Text1_KeyPress(KeyAscii As Integer)
If KeyAscii = 49 Then KeyAscii = 0
End Sub
In the form's properties, set Key Preview to True.
Add this code to your form. It says if the 1 key is pressed, then the Command button's click event is called. If you want to use the Keypad then Numlock has to be set first or it won't work.
Code:
Private Sub Form_KeyPress(KeyAscii As Integer)
If KeyAscii = 49 Then Command1_Click
End Sub