voxus that's a long solution if what i'm saying is true

first) see how many running processes there are in the background

second) find out if any of them are taking x amount of your processor at a time

third) post a screenshot here so i can see and help

fourth) disable the processes running that would be bogging you down (if any) through msconfig

fifth) run disk cleanup THEN defragment hdd

after this quick guide all should work that much more smoothly and you wont have to reinstall windows (although that option would work it takes longer)