Maybe this can help you (change color in cell next to input one)
Private Sub Worksheet_Change(ByVal Target As Range)
If Target.Column = 3 Then
ThisRow = Target.Row
If Target.Formula > 100 Then
Range("D" & ThisRow).Interior.ColorIndex = 3
Else
Range("D" & ThisRow).Interior.ColorIndex = xlColorIndexNone
End If
End If
End Su
You could do it with conditional formatting (CF) ..
Example:
Select col A
Click Formatting > Conditional Formatting
Make the settings under Condition 1:
Formula Is | =NOT(ISBLANK(A1))
Click Format button > Patterns tab > light green > OK
Click OK at the main dialog
Try entering something in any cell in col A
The fill color "light green" will appear in the cell