Time limited demos with full functionality are very easy to crack.
I recommend you create an unlimited demo, that doesn't have full functionality. For example, some very important functions won't work in the demo.

You can do it easily with directives.
Code:
#Const DemoVersion = 1

' ....
#If DemoVersion = 1 Then
Call MsgBox("This function is not available in the demo version of " & App.Title & "!", vbCritical)
#Else
DoSomething
#End If
The #If, #Else and #End If directives tell the compiler what to compile. In that case, only this will be compiled:
Code:
Call MsgBox("This function is not available in the demo version of " & App.Title & "!", vbCritical)
If you change the #Const to 0, only the DoSomething will be compiled.