Vba Searching Problem

Hi Highly Esteemed,

I have an Excel workbook with two Columns A and B. I also have another column H which I want to populate depending on which keywords were found in A or B.

A - contains the subject of a message.
B - contains the message body itself (mean 1000 - 1200 characters).

What I want to do is of this nature:

Do Until end of used range
Activate the Cell I want to populate
Use instr() function to search cell A2 (increases with loop)
If keyword found (eg. downloading) in A2 then H2 = internet
If not found
                Make the search string column B (for the same record)
Repeat the search for this column (same record)
If keyword found, then populate H2
  else put "undefined" in H2
. 
 end if
     end if
loop 

Now my VBA implementation works but is not very accurate - also the presence of too many if then...if then.... makes it inaccurate - I was wondering if anyone could help me code select case statements using instr() or any other suggestions. 

Here is a section of my code: 

Private Sub cmdReqClass_Click()
'RequestClass
'Sub RequestClass()
Dim SearchString, SearchChar, MyPos
Sheets("DataRecord").Select
Range("H2").Select

    'character strings containing root words to be searched.
  
    Searchinternet = "INTERN"
    Searchpassword = "PURC"
    SearchCharPrint = "PRINT"

'There are about 25 search strings in total
    Do Until Selection.Offset(0, -7).Value = ""
    SearchString = (UCase(Selection.Offset(0, -7).Value))

    ' String to search in.
     ' A textual comparison starting at position 1
     
     
     
    If (InStr(1, SearchString, Searchinternet, 1) > 0)  Then
      ActiveCell.Value = "Internet Related"
     
    ElseIf ((InStr(1, SearchString, SearchCharPrint , 1) > 0)      ActiveCell.Value = "Printing"

    Else
    ActiveCell.Value = "Undefined"
    HERE IS MY PROBLEM - I DONT KNOW HOW TO WRITE THE CODE TO SEARCH B2 FOR THE SAME RECORD NEATLY - I DONT KNOW HOW TO USE SELECT CASE IN THIS SITUATION AND IF IT IS APPROPRIATE!  
         'SearchString = (UCase(Selection.Offset(0, -13).Value)))
          Select Case InStr(1, UCase(Selection.Offset(0, -6).Value), SEARCHINTERNET, 1)
           
            Case Is > 0
                ActiveCell.Value = "Internet Related"

            Case Is < 0
            InStr(1, UCase(Selection.Offset(0, -6).Value), SearchPass, 1)
            
            Case Else
             ActiveCell.Value = "Undefined"
            End Select

    End If
    
    
Selection.Offset(1, 0).Select
Loop
End Sub