... but when I go to switch from the default workgroup to the domain in System Properties, the entire domain box is completely grayed out and inaccessible. I am running the command
from a local administrator account on the computer with the <strike>appropriate permissions</strike>, not from a Live ID.
Try using a domain administrator account (regarding appropriate permissions for network administration).
The local administrator account only has administrative access to local resources on the PC - i.e. does not have administrative privileges on the network
Regarding access and use of a domain administrator
I.e. you're a user at your company - so you should contact your companys system administrator regarding company policy.
I.e. if this is BYOD (your own device) it will probably not be joined to the domain.
If its a company workstation (laptop) - he will rejoin it to the domain.
As a rule of thumb - and may be confusing you here, do not expect yourself - even though a superuser with local administrative privileges - to finalize redeployment of windows, apps and data in a company domain. I.e. in a company you usually don't control
access to payrolls etc. (you should not have that kind of administrative configuration access - even if a company owner you could mess things up giving "unauthorized" access. Even a domain administrative account is not used as a "user" account - only configuration).
I.e. with user accounts i.e. local administrator you don't control access to private network ressources in the company. I.e. you cannot join network ressources - joining to a domain means connecting with the private web service in the company basically controlling
identification and internal access to company wide resources. So that service hides some complexity as well.
Delegate the job to your companys system administrator and let him complete the work if this is a company workstation
... that you may have reinstalled yourself using the local administrator account without using the companys deployment services - i.e. automated deployment (i.e. PXE network boot to the companys Windows Deployment Services or Symantec
Altiris etc.). If no automated deployment is available at your company then the component (responsibility) of deployment services are manually executed by the system administrator (automated deployment availability at your company will typically depend
upon complexity i.e. the number of computers owned by your company - but even for a small number of workstations the benefit of Windows Deployment Services is great ...)
Basically, the finalization of software configuration for a company managed computer must in part be managed by the system administrator, i.e. rejoining the computer to a domain - which effectively means the administration of the computer from this point
on is delegated to the domain controller and thus automated management of i.e. authentication and authorizations.