before you reinstall - make sure you do not have any apps that start automatically at start up..
go to your system prefs and then accounts and then select your user and select your login items and delete what is there.
quit all apps and then reboot and have a try..
if it is fine with other uses means its your user that is messed up, not OS
Apple MacBook Pro 13" Retina 2.6GHZ i5 16GBs/512SSD/128GB Flash storage Storedge
Apple Thunderbolt display 27", K750 Solar Keyboard
Logitech Wireless Trackball M570
LaCie Stark 1TB for time machine, Apple Track Pad
Moshi Keyboard cover ( to catch the drool when surfing rumor sites )
Government jobs / work places : it smells like wet dogs, so do some people that work there. Everyone moves like they were injured!, It's like a low budget rehab centre