Problems with exe.exml

Hi,Please, please please can some one help, I am at my wits end. A few days ago, out of the blue, I noticed that various things were not loading via the exe.xml file. What is extremely odd is that the file not only is not loading stuff but is also seems to be affecting things in the dll.exml file. For example, Contrails Pro which used to appear as an item in the Add-Ons drop down menu no longer does. But weirder and weirder, last night I did a new exe.xml file with no items in it and it workded - a miracle - I added AI carriers to it and it still worked. I tried again this morning it was still working - both Contrail Pro and Ai carriers were appearing as items in the Add-ons drop down menu. However, now after restarting the computer this afternoon the very same problem has re-appeared over again. The only items appearing in the Add-ons drop down menu are PMDG and Fsuipc, nothing else. I did and experiment deleting the exe.xml file completely but the problem with the missing menu items continues and if I populate the exe file with items none of them load.I should be very grateful for some suggestions as to how to fix this problem.Thanks,Adam.