Vista & Multiplayer Fatal Error - Shot in the Dark

Hi folks,I have both SP1 and SP2 installed and sometimes when I am in multiplayer the screen will freeze after quite some time flying. FSX restarts with precious little information other than "FSX encoutered a fatal error and is restarting". I appreciate this is very much a shot in the dark asking if anyone has any ideas on how to correct the problem of if anyone else has had a similar experience. Could it be attributed to Gamespy? - I note many complaints about this platform for Multiplayer.Previous troubles with out of memory errors have been corrected via the various links in the forum and following the solutions.I have a fairly top end machine running Vista 32bit ops system. The Vista reporting shows the following information - hope it means something to someone!......QUOTEProblem signatureProblem Event Name: APPCRASHApplication Name: fsx.exeApplication Version: 10.0.61472.0Application Timestamp: 475e17d3Fault Module Name: sim1.dllFault Module Version: 10.0.61472.0Fault Module Timestamp: 475e180dException Code: c0000005Exception Offset: 0006df64OS Version: 6.0.6000.2.0.0.768.3Locale ID: 2057Extra information about the problemLCID: 2057Bucket ID: 594672225UNQUOTEThe driver version for my video card is: 7.15.11.6925 dated 11/12/2007.Any suggestions appreciated - thanks.David