Fsx steam edition - 737 ngx pmdg help

Hi, I've recently purchased the 737NGX. Install went fine. Installed simconnect as advised with SE edition. Loaded aircraft, all works fine with cold and dark start until about 10-15 minutes into the startup of aircraft when keyboard shortcuts no longer work, and no longer able to use mouse cursor to click anything on the VC. Closed and reloaded, same issue again. Cursor when using any button on keyboard appears as a clicking index finger. Running up to date version of FSX SE, FSpassengers installed but not operational at that pint, and active sky next installed and running in background. I've contacted the pmdg help desk but no one has got back to me and it's kind of annoying me now as I've spent $60 on the plane but have yet to be able to even fly it. Thanks