FSX default airport scenery missing

Hi ,

After months of happy flying a while back I noticed there was a reduction in the amount of global autogen and scenery around , for example , after a departure out of luton all I could see was fields ,which is incorrect I would usually see alot of trees and houses. I hadn't noticed any problem apart from that as I was only flying in the UK and for the airports I fly at I have UK2000 scenery which was working fine. I had then noticed at WSSS ,which had default scenery, all airport terminals where gone apart from jetways which where floating. I tried other default airports and they where the same.

PC specs- 

Windows 7 64bit

i7 2600 @ 3.40GHz

8gb RAM

GT545 GDDR5 1gb

Thanks ,

Arun