Hi all
I have this code where the first inputbox asks the user to insert year e.g. 2011 and second inputbox asks to enter week number e.g. 52.
How can validate that user indeed selected the a valid year number lets say number between 2000 and 2100 (yes I believe no one will use excel in its current form after 2100 ), and with week number it can be number between 1 and 52. Error handler should exit the sub and prompt with a message. Like "not a valid year" or "not valid week number"

Code itself looks following:
Sub charts_by_wk_number()
Sheets("Chart_data").Visible = True
wkYear = InputBox("Please insert the current year." & Chr(13) & Chr(13) & "Type in exactly 4 numbers e.g. 2011", "Insert current year", "2011")
wkNo = Application.InputBox("Please type in the week number e.g. number between 1 to 52")
Sheets("Chart_data").Select
Range("chart_year").Value = wkYear
Range("chart_week_number").Value = wkNo
Range("A1").Select
ActiveCell.FormulaR1C1 = _
    "=DATE(chart_year,1,chart_week_number*7-2)-WEEKDAY(DATE(chart_year,1,3))"
Range("chart_date_end").Select
    ActiveCell.FormulaR1C1 = "=chart_date_start+6"
Range("chart_date_info_concatenation").Select
ActiveCell.FormulaR1C1 = _
    "=IF(chart_week_number="""",CONCATENATE("" ("",TEXT(chart_date_start,""dd/mm/yy""),"" - "",TEXT(chart_date_end,""dd/mm/yy""),"")""),CONCATENATE("" (week "",chart_week_number,""; "",TEXT(chart_date_start,""dd/mm/yy""),"" - "",TEXT(chart_date_end,""dd/mm/yy""),"")""))"
Range("A1:E1").Value = Range("A1:E1").Value
Call continue_code
End Sub
If anyone knows how to do it, I would appreciate the help.
Cheers
Rain