Delete registry after year Vb net - vb.net

Question

How can I make my licence works only one year? When I activated my program I add registry with current date. On each run I check if the registry exist. If registry exists I can use my application otherwise it prompt me to activate it .
I want to make that my licence works only one year.
I tried with
Public Sub Licence_Check()
Dim licenca As Date
Dim days As Integer
licenca = CDate(My.Computer.Registry.GetValue("HKEY_CURRENT_USER\tFull", "tFull", Nothing))
days = CInt(365 - (DateDiff(DateInterval.Day, licenca, Now)))
If days <= 0 Then
My.Computer.Registry.CurrentUser.DeleteValue("tFull")
pbInfo.Value = pbInfo.Maximum
gpbInfo.Text = "One year Licence OVER"
RbContinue.Enabled = False
End If
End Sub

Answer 1

I have already warned you about the weakness of this approach, but this is how you could write the above License_Check
Public Sub Licence_Check()
Dim licenca As Date
Using tempKey = My.Computer.Registry.CurrentUser.OpenSubKey("Software\YourAppNameHere", true)
licenca = CDate(tempKey.GetValue("InstallDate", Nothing))
Dim limit = licenca.AddYears(1)
if limit < DateTime.Today
tempKey.DeleteValue("InstallDate")
Console.WriteLine ("One year Licence OVER")
End If
End Using
End Sub
Notice that you should store your application info in a subkey of the SOFTWARE subkey and not directly under the root HKEY_CURRENT_USER. Then you need to open the appropriate subkey asking for the write permissions and finally read the value desidered.
To check the dates just add 1 year to the value read and do the check against Today.
To delete you should use the DeleteValue method of the opened subkey.
Also I suppose that this is not a check that should be applied on a user by user base. Instead it is a check that could be applied to the whole application. In this case you should use the predefined My.Computer.Registry.LocalMachine registry key.