Workgroup is just like peer to peer network, it can allow each other to access, files, internet, printers and etc but with less security. There is no centralized management in a workgroup so each and every systems will react like client as well as server.

Domain is a type of client/ server technology with centralized management, security, easy files, printers and internet sharing with other systems. One server will control all the systems and and allows which users have access to which files.

RAM means Random Access Memory, is a Hardware component will store the datas temporarily for quick access. Once you Power off the system data will be deleted.

Below things to be considered if network card is showing yellow symbol.

1) Check IP address is properly configured,
2) check DNS is pinging or not
3) Check dns is properly configured
4) Check and update Network Card Driver.

Following things to be checked in the PC to resolve the internet issue.

1) Check Public network access is allowed or not in Firewall, If blocked we should allow for internet access.
2) Check Firewall is blocking outbound access or not.
3) Check the proxy settings in Internet options
4) Make sure correct dns is configured or not.
5) Make sure dns server is pinging.