FS hangs

When I change a task during flying, f.e. click Squawkbox or FS is reading the Harddisk f.e. wheather change or extracting flaps, FS2002 hangs. The problem is that this is happening pure random. Sometimes it happens after a couple of hours flying and sometimes right after the start of a flight.My system specifics are:Mainbord P3 Chaintech 7ctkjd 2 GB512 Mb RAMtwo harddisks (9Gb + 30Gb)Viper TNT2 Pro VideocardSoundcard is inegrated in MainbordSpecifics FS2002:FS2002 proPss 747-400 aircraftSquawkboxRoger WilcoSi131Thanks for help.RegardsLuke The Netherlands