I am running Windows7 64 bit and I cannot get past the first blue start up screen. There are no messages or anything - it just stays on that screen. I have been using it for a long time and this just happened. I have uninstalled and reinstalled it and I have the same problem. I sure hope you have a solution for this as I am very upset.

Could be caused by a corrupted log book file.Try to move the file Logbook.BIN from the folder C:\Users\your_logon_name\Documents\Flight Simulator X Files to your desktop and try to start FSX again.If this wasn't the cause you may move the logbook.bin file back.