[vba]
StbyStn = "LSR" & ThisWorkbook.Sheets("Pump").Range("F501").Value & ".xls"
On Error Resume Next
Set wb = Workbooks(StbyStn)
If wb Is Nothing Then Set wb = Workbooks.Open("C:\Users\Richard\Documents\" & StbyStn)
On Error GoTo 0
Workbooks(StbyStn).Activate
[/vba]