What exact model Dell? There might be a service manual I'll reference here.
I have a U2312HM Dell monitor and a 4 year old Dell Inspiron desktop with Windows 10. The Device quit connecting to the wireless mouse. I tried a corded optical mouse but didn't work. I tried every USB port and none would light up the mouse. Since it won't connect to either type of mouse I can't get on line to any troubleshooting. I would be most thankful for any suggestions.