Hi Grittyminder,
Deleting a few reg entries is not going to give you clean uninstall, though you may get a workable product. You can run this to get a better result: http://labs.adobe.com/downloads/acrobatcleaner.html.
While I'm not sure what the problem is, it would be worth verifying the product version using the MSI API as decribed in the admin guide at www.adobe.com/go/acrobatetk.
Ben