Hi alli have just done a clean install of FSX+sp2 then all my addons, and when i load PMDG 747-400x for the first time all is good,but if i select a different 747-400x aircaft all the system's of off in the cockpit(like cold and dark).I have install the updata for it the 747,can anybody help pleasemarkAMD6400+9800GTX+3gig memvisata 32bit +sp1FSX+sp1+sp2

That's a known problem with FSX. Anytime you load the same engine variant again there are going to be problems, try loading a different engine. That should work.