errr...i dont know! i just plugged the phone in and opened up the 900 on the windows 'my computer' and found the n900 backup folder,found the most recent file and dragged that onto the desktop....

just thought i would post an update in case it helped other people....
i did a full flash inc emmc and it all worked great UNTIL i did the restore from the memory card then the exact same problem came straight back!!
so i synched what i could to my old n79 and then did another full flash with emmc and then synched back to the n900 and success!! all fixed and working wondefully.no idea what did it but it wasnt happy with something!!!
thanks again guys for all your help