SOLVED : Completely removed HDD sentinel , cleaned up the registry , removed any mentions , also deleted the task from the task scheduler (found myself). Spent almost an hour !
Rebooted , installed another version , voila : everything works !
What I really hate about this "sentinel" , it is always outdated ! It won't show the info about my HGST from 2015 , c'mon , really !?
Is there any other similar (but better) tool that can check disk temps with an interval ?
EVERYONE , including jaclaz and Dixel , thank you for your help !!!