HarryButcher.co.uk

Hey, I'm trying to render a fairly heavy scene and everything starts well - CPU meters on full, fans ramping up.. then everything goes calm and I see less/no progress in the render image.. even allowing it to run overnight. Any Ideas? I've been successfully outputting the same scene (mostly) all week and it's been fine.. only changes are a 3D human model and a different amount of lighting.. Ta,