I too am having this same issue. I have deleted a bunch of games and such off my computer and yet it still does it. Same problem with Operation Mania. Both of these games run extremely slow. I have no problems with any other games. This game ran fine til I got to the hospital with the two floors and then it drags. So knowing that I really doubt that my computer has too many files on it!
 

These levels are hard. The best I can tell you is to chain as much as you can and try to match as many colors as you can. If there is a podium, use that whenever you can to keep customers in line happy. Serve snacks or dessert if they have it. And do not sit any noisy customers next to ones who hate noise or they leave. Sometimes it takes many tries for me to get expert but it can be done. Good Luck