I have opened two qvw's from community in my desktop personal edition from then I could not even access my existing applications created earlier. Is there a way apart from license lease in order to recover them.
When you start QlikView Desktop Personal Edition for the first time, you create one "user key", then you can create and read your own apps which will use that first key.
If you download 1 app, you will see the notification message, if you accept, you consume 1 user key change (2 out of 4, 2 remaining). If you open an additional app, that's a new user key change.
When you go back to the app you created in the first place, you need to update that user key once again, and that exhausts the 4 changes. Bear in mind that since you recovered one of the downloaded applications, you cannot open yours any longer (the user key has changed, it will count as a recovery attempt).
As a final note, when downloading apps from the Qlik Community, apps built by Qlik staff can be converted to be used with Personal Edition, contact the author and see whether the app can be converted to be open by Personal Edition without using one of the changes.