loading bar popping up

hello all, can anyone help, i have just installed vista 32 bit and fsx, ive installed various addons but heres the problem. i load up a flight then bang,the screen blacks out and the fsx loading box pops up with loaded 100% in it.it then goes back to normal but when i change view it blacks out again,sticks for around 5-10 seconds and back to normal but this keeps happening and is so frustrating as i seem to be spending more time trying to get around problems than i am using this simulator ive invested so much bloody money into.ive got sp1+2 installed, the latest drivers (that im aware of) and all the latest updates for vista.the aircraft in question when this is happening are airbus series vol1 and 737 pic (just flight).please helpchris