Adding Expiration Date on my Program

Hi,
can someone tell me a way to put an expiration date on my program, kind of like being an evaluation version or a trialware. Pls tell me as many ways as possible, so i can compare.


many thanx~!~!

sample created by Reginald Wheat

VB Code:

Option Explicit
 
Public Function DateGood(NumDays As Integer) As Boolean
    'The purpose of this module is to allow you to place a time
    'limit on the unregistered use of your shareware application.
    'This module can not be defeated by rolling back the system clock.
    'Simply call the DateGood function when your application is first
    'loading, passing it the number of days it can be used without
    'registering.
    '
    'Ex: If DateGood(30)=False Then
    ' CrippleApplication
    ' End if
    'Register Parameters:
    ' CRD: Current Run Date
    ' LRD: Last Run Date
    ' FRD: First Run Date
 
    Dim TmpCRD As Date
    Dim TmpLRD As Date
    Dim TmpFRD As Date
 
    TmpCRD = Format(Now, "m/d/yy")
    TmpLRD = GetSetting(App.EXEName, "Param", "LRD", "1/1/2000")
    TmpFRD = GetSetting(App.EXEName, "Param", "FRD", "1/1/2000")
    DateGood = False
 
    'If this is the applications first load, write initial settings
    'to the register
    If TmpLRD = "1/1/2000" Then
        SaveSetting App.EXEName, "Param", "LRD", TmpCRD
        SaveSetting App.EXEName, "Param", "FRD", TmpCRD
    End If
    'Read LRD and FRD from register
    TmpLRD = GetSetting(App.EXEName, "Param", "LRD", "1/1/2000")
    TmpFRD = GetSetting(App.EXEName, "Param", "FRD", "1/1/2000")
 
    If TmpFRD > TmpCRD Then 'System clock rolled back
        DateGood = False
    ElseIf Now > DateAdd("d", NumDays, TmpFRD) Then 'Expiration expired
        DateGood = False
    ElseIf TmpCRD > TmpLRD Then 'Everything OK write New LRD date
        SaveSetting App.EXEName, "Param", "LRD", TmpCRD
        DateGood = True
    ElseIf TmpCRD = Format(TmpLRD, "m/d/yy") Then
        DateGood = True
    Else
        DateGood = False
    End If
End Function
 
 
'Usage 
 
 Private Sub Form_Activate()
    If Not DateGood(30) Then
        MsgBox "Trial Period Expired!", vbExclamation, "Unregistered application"
        Unload Me
    End If
End Sub

Thanx man, this is absolutely PERFECT!
neat and tidy, wish i can one day write a code to the same standard as this!