Search 2 Columns Of Information

I have the following code below, im not sure how to modify it to make it only search 2 columns of information, how can do this?

Private Sub CommandButton3_Click()
Dim StrFindWhat As Range
Dim NextCell As Range
Dim WhatToFind As Variant

WhatToFind = Application.InputBox("Please enter the Application or Service you want to search for?", "Search", , 500, 80, , , 2)
If WhatToFind "" And Not WhatToFind = False Then
For Each oSheet In ActiveWorkbook.Worksheets
oSheet.Activate
oSheet.[b4].Activate.....................