InfoPath Dev

I have a form library in SP. Users can click 'New' to create a new form, then they click a 'Register' button which submits the form

Problem: If they click 'New' then 'Register' again this overwrites the form and they loose all the data they had on the previous form. I need to find a way to check if the filename already exists before.

Can this be done using a rule?? I have a data connection to the form library, but can't figure out how to search it. Also the Register button uses VBScript, heres what i have so far

Sub btnRegister_OnClick(eventObj)

 userChoice = XDocument.UI.Confirm("Are you sure your registration details are correct?", 4)
 
 If userChoice = 6 Then
  
  XDocument.DOM.selectSingleNode("my:myFields/my:Current_Status").Text = "New PPR Form" 
  XDocument.DOM.selectSingleNode("my:myFields/my:Submitted").Text = 1
  XDocument.Submit()
  XDocument.View.Window.Close(true)

 Else
 
  XDocument.UI.Alert("Please contact Human Resources to amend your details")
  XDocument.View.Window.Close(true)
 
 End If
End Sub

Sorry for replying late.I thought by the time u must have found a solution to ur problem.If not,then shile creating a dataconnection to submit a form to ur library,u have to define the url of ur form library and then in the second row,instead of submitting it with a name form,select some unique function for that click on Fx button and select now() from the list.Now when u'll submit the form it wont get overwrite..

Let me know if u still face this issue..