HELP!

Problem:  While FS2002Pro is running in flight mode reguardless of the aircraft or settings at various intervals the game freezes up with what seems to be a continuous sound loop like a high pitched squeel.  The only remedy seems to be a hard boot of the system.

Background:  I am running FS2002PRO on a windows 2000 pro OS, I have an nvidia geforce 2 MX video card, Creative audigy SB sound card, 1 gig of RAM, with an AMD 900 Duron processor. 

What I have already tried:  I have scanned for bad BGL's, I have reduced all sliders to their lowest settings, I have had the problem with both add on and default aircraft, I have checked FSUIPC's log for any issues, my framerates are good 23 - 32 on average, right up till the system freezes up.  I have tried the latest drivers as well as older ones for my sound card and video card, my direct x is up to date as well. I have tried to make sure that no other programs are running in the background,

I am out of things to try, can someone please offer any suggestions?