i have recently purcased (04/2007) a house, 100 years old. Which had new pvc windows and door installed 2006.
Recently after some heavy rain, the living room window started leaking, from the celing on the inside of the window, above the sill, (best way to describe where the window is in the wall, there).
when i viewed the house, (still is now,) the plaster board was missing, and i was told a leak had been fixed, just hadn't replaced this board. but leaked again, sellers said far as they new was fixed, because after some heavy rain no leaks.
they never given me any details of the leak, just it leaked...

have been given some pointers but have been away from home and haven't got to check...
flashing, guttering (i know works, and is well clear of this window, what i think could be the cause, is the windows sills on the next floor not sloping away enough and holding water, could this be the cause?

any suggestions to help me following the wrong path would be great,
Thank you