Loop Sheets, Find Value & Test Condition

I want to search a column, from A30 moving up to A10 for the first value in excess of 0.

Having found the value the search stops and I want to select the cell next to it in B column.

Then I want to check if a value in B column exists. If no value exists I want to enter a fixed value from another sheet.

If a value does exist I want to take no action and move on to Column C to repeat the checking process for columns C and D.

Then I want to move to the next spreadsheet and repeat the process.

The code I have written so far is below and I just can't get it to work.

I have attached a spreadsheet to illustrate the problem.

Sub Closingdata()

Dim a As Integer
Dim b As Integer
Dim rngOutput As Range
Dim shtTemp As Worksheet
Dim vntName As Variant

For Each vntName In Array("sheet1", "sheet2")
Set shtTemp = Worksheets(vntName)

shtTemp.Select
shtTemp.Range("a30").Select
Do Until ActiveCell.Value > 0
If ActiveCell.Value > 0 Then
ActiveCell.Select
Exit Do
End If