iMac slow startups but really slow shutdowns.

Had a problem with slow startups and shutdowns which continued to get worse. Stumbled onto resolution. Shutdowns and startups continued to slow down. Found in Activity Monitor that HP scheduler kept running. computer log showed several "halt" at shutdown. Went into Accounts-Login Tab- Found 3 HP programs which loaded when I had a HP printer driver update. They should have uninstalled after the driver update but continued to run. Deleting the HP files from this tab did not cause any problems with my printer. My iMac is back to its normal "fast" startups and shutdowns. Anyone with a HP printer may want to look here if they are having problems.