Did you check with task manager ,application,processes ?. Sometimes certain files keep running if PD did not close properly.
PC specs :
OS Windows 10.0 Pro
MB - AS rock Z77 extreme 11
Intel 3770K @ 4.0 Ghz OC
Gskill 32 GB RAM 1800 Mhz
6 TB HDD, SSD bootable
nVidia ASUS GTX 660 Ti
BenQ 22" LCD monitor 1920x1080