yeah qtp3 definitely lol, you could still try to just reinstall the game, i mean, it won't mess up your game, just that if after you reinstalled and you see purple places, or textures that reverted to the original vanilla version, then that just means you gotta reinstall qtp3 again (re overwriting textures etc), so redownloading yes

at least you don't have problems with the game itself...
OR just an idea, i'm not completely sure on this, but maybe it's possible to backup your data folders, and after resinstall just overwrite the new folders with the backup ones. your textures will be there, and your esp will be there..so it should run ok. i'm not 100% sure though.