my system preferences wont open on my iMac safari

my System Preferences wont open open my iMac with safari. I was told to go to iCloud.com and under account settings go to reset data and documents and follow the prompts. there is no reset data and documents there. I Mac OS X and disc utility and followed the instructions but that did not bring back the system preference either. it just disappeared. I don't know if I did something or the computer which is old did something. my computer has high Sierra and is a mid2011 model (10.13.3). thank you