I spent ages on this!! Basically after you have followed all the different walkthroughs that say exactly the same thing.... When you've combined the 2 sections of the spring, had the magnifying glass tool on it, given it to Greg you've then got to go back to the microscope in the lab and have another look at the 4th photo of the engine!!!!! BINGO then Catherine prattles on blah blah blah and Lesley will drop Corey in it letting you get your interrogation!!!