My O/S had a problem and Windows decided to do a roll back. Consequently, my 737NGX became corrupted.I tried to re-install it from the begining, but it advised me I had the SP1 version with 600/700 expansion and that I would need to un-install the whole package before I could re-install it. The un-install was also corrupted and therefore I can't un-install in order to re-install everything.The proagram is theer on on c:/ drive, but FSX can't see it. I thought the airctaft.cfg files were changed, but even after tinkering with them, it still won't work.I re-installed the SP1 and 600/700 expansion, but with very limited success.Can anyone provide a solution to this? Perhaps someone could give me some guidance to manually delete the files off C:/ and the windows registry so that I can convince the PMDG installer that 737NGX is not already installed.Any help would be much appreciated.Oisin McAsey