Private Function IsAdobe9Installed() As Boolean IsAdobe9Installed = False Dim AdobeKey As RegistryKey = Registry.CurrentUser.OpenSubKey("Software").OpenSubKey("Adobe") If Not AdobeKey Is Nothing Then Dim ReaderKey As RegistryKey = AdobeKey.OpenSubKey("Acrobat Reader") If Not ReaderKey Is Nothing Then Dim AcrobatReaderVersions As String() = ReaderKey.GetSubKeyNames() Dim LatestVersion = (From VersionKey In AcrobatReaderVersions Order By VersionKey Descending Select VersionKey).FirstOrDefault If CDbl(LatestVersion) >= 9 Then IsAdobe9Installed = True End If End If End Function