Convert License Type > Enter the Product Key is greyed out

I've been reading up on this a bit. I'm not sure why it occurred. I downloaded SP Server 2010 and the Key from MSDN. There were no references to "Trial" or anything of that kind.

It appears that there are several suggested possible solutions:

1. Recreate farm: not going to happen. Starting all over is not an option.
2. Temporarily disable Antivirus protection and install new Key.
3. Detatch and reattach the Sharepoint_Config DB: this would, I believe, mean I'd have to close connections to all farm WFEs, detatch the DB, and then reattach, and see if the box is still greyed out.
4. Unsupported SQL query

Any other options? Other than 1, are any of these the generally accepted method?

Thanks,

Scott