Its also a tad slow, ran malwarebytes and avast, nothing..
You need to be a bit more specific, your problem can be one of many:
1. is the standby option greyed out?
2. when you press standby nothing happens
3. after walking away from your computer it does not go into standby
4. you set it to go into standby after a certain amount of time and it does not go into standby
I would write the solution for each one but would be easier if you specified the exact problem. #3 soulution is like others wrote, make sure the power settings is set to go into standby after a set amount of time idle (power options is found in start > control panel > power options)