... my sims has started crashing and i'm certain its not cc or anything else as i haven't changed anything at all on my computer since last gameplay.
Actually it could be CC. It would helpful to know what the circumstances are when the crash occurs.
Crashes that occur in CAS or when trying to change the appearance of a sim could be happening because of a bad mesh, requiring an EP/SP you don't have or a corrupted file. It may not have crashed before because you hadn't tried to use it.
Townies and NPCs that are slated to use a bad mesh can cause the game to crash whenever that sim is to appear.
Bad object/furniture meshes will cause the game to crash when that object is attempted to be placed, or if it's in a downloaded lot, when you attempt to enter that lot.
I've had bad meshes in my game for months before they caused a crash because I never tried to actually USE it before. The mesh will load in memory at startup, but it cannot be displayed. When I try to display it, whether by scrolling through Bodyshop/CAS CC or placing it on my sim/lot, I finally had the crash. Since then I've found that mods/hacks not compatible will cause Object Errors or "jump bugs"; meshes not compatible or corrupt will cause the game to crash.