FSX hanging

HiI need help identifying a system hang error please.I have just installed Horizons Gen X photo scenery version 3 with no problems and defragging inbetween volumes.Tried a quick flight and no problems.Then I put on Treescapes and again defragged the drive.Next updated my UT2 summer schedule to summer 2011.I tried FSX again,but this time I get a hang on the main menu screen,which then gives a no response .The error log shows the following.  Description:  A problem caused this program to stop interacting with Windows.Problem signature:  Problem Event Name:    AppHangB1  Application Name:    fsx.exe  Application Version:    10.0.61472.0  Application Timestamp:    475e17d3  Hang Signature:    78b6  Hang Type:    0  OS Version:    6.1.7601.2.1.0.768.3  Locale ID:    2057  Additional Hang Signature 1:    78b69d5f01e572b0cf4b3054af565685  Additional Hang Signature 2:    b354  Additional Hang Signature 3:    b35482de5074cab06e2afa53cf90a479  Additional Hang Signature 4:    78b6  Additional Hang Signature 5:    78b69d5f01e572b0cf4b3054af565685  Additional Hang Signature 6:    b354  Additional Hang Signature 7:    b35482de5074cab06e2afa53cf90a479I've searched and found a few similar problems but no solutions.Anyone any ideas please.ThanksWhiskeyBravo