Excel Loop VBA

If Range("C16") <> Null Then
    If Range("D16") <> Null Then
        Range("D16") = CommitNumber.TextBox1.Value + 1
    Else
        Range("D17") = CommitNumber.TextBox1.Value + 1
    End If
End If

What is CommitNumber?

CommitNumber is this module which is the source for the text box on the User Form.

Is there not a way to loop this?  This will have to go throught Column C about 30 rows checking to see if it is not null add 1 to CommitNumber.  The example of the commitNumber would be 5000 then the next one would be 5001 if Column C is not null.

Thank you both for looking.
'//////////////////////////////////////////////////
Public Conn As ADODB.Connection
Public rsCommit As ADODB.Recordset
Public rs2NewLastCommitNumber As ADODB.Recordset

Public Sub OpenADOCommitNumber()
    Dim dbpath As String
   
    'With Password
   dbpath = "Data Source=\\Volume.mdb;Jet OLEDB:Database Password=mandatory;"

     
   
    Set Conn = New ADODB.Connection
    With Conn
        .Provider = "Microsoft.Jet.OLEDB.4.0"
        .Open dbpath
    End With
   
        Set rsCommit = New ADODB.Recordset
    With rsCommit
        .Open UCase(fOSUserName) & "Commit", Conn, adOpenDynamic, adLockOptimistic, adCmdTable
        CommitNumber.TextBox1.Value = .Fields(0).Value + 1
       
    End With
   
    Set rs2NewLastCommitNumber = New ADODB.Recordset
    With rs2NewLastCommitNumber
        .Open UCase(fOSUserName) & "NewLastCommitNumber", Conn, adOpenDynamic, adLockOptimistic, adCmdTable
        CommitNumber.TextBox2.Value = .Fields(0).Value

   
     
    End With
   
End Sub

What does the ADO code shown above have to do with the loop you are wanting? Are we to loop through the rows in the Recordset and update the spreadsheet?

I need a bit more info in order to proceed, sorry.

The commitNumber is only populated once.  Then I need the code to just add one to that numbe(5000)r if Column C is not null(5001), then go to the next, if Column C is not null add 1(5002) but if not skip that number and go to the next.  

     Col              A           B                  C                D
 Row15             4.5       100          10000000       5000
 Row 16
 Row 17           5.5        100         100000000     5001
 Row 18           5.5        100         100000000     5002
 Row 19
 Row 20           5.5        100         100000000     5003
etc...

No worries - glad to help.