After installing SP1 I initiated FSX and start to load the a/c. Engines start running during the "countdown" of systems installations. However when the countdown is ended immediately there is a rattling noise and indication of engine failure. After a couple of seconds all alarm bells and whistles start to come alive. So I followed the instructions again and uninstalled/reinstalled the 737NGX completely to start clean. Did run the SP1 installer after the re-install. Starting up the 737 NGX delivers the same performance: engine failure, lot of noise and a slow but surely melt down of the a/c.Any idea where this is coming from?

After installing SP1 I initiated FSX and start to load the a/c. Engines start running during the "countdown" of systems installations. However when the countdown is ended immediately there is a rattling noise and indication of engine failure. After a couple of seconds all alarm bells and whistles start to come alive. So I followed the instructions again and uninstalled/reinstalled the 737NGX completely to start clean. Did run the SP1 installer after the re-install. Starting up the 737 NGX delivers the same performance: engine failure, lot of noise and a slow but surely melt down of the a/c.Any idea where this is coming from?

have you tried starting up the flight with all hardware controllers disconnected?Are you able to access the PMDG menu (via the FMC CDU) and check all failures are cleared?

I think I found out what went wrong. I realized that I needed to run the programs as an admin. So I changed that and restarted. Until now the a/c startup is normal. Hope for the best.Thanks for your support.

Yeah, in Windows Vista and Windows 7, you should pretty much run anything as Admin if you want it to communicate with something else.