FSX/Acceleration -freezes my game

I have a good spec pc(xp), i run a nvid 7900 gs card,fsx deluxe sp1 etc, all
was well till i added accel package, with this installed i cant use the
normal task bar options in freeflight or online (alt key) everytime i go to
different view/make my screen larger/smaller/change to a different airport
etc, the game freezes, normally a reboot is the only way back, i uninstalled
accel and all works fine, contacting microsoft is harder than suggested
unless your prepared for a hefty telephone bill.. any ideas.

regards
Dave