Wait a minute....

I've installed SQL 2005 a few zillion times and, unless my memory is failing miserably, I do not remember anyplace to enter the company name during installation.

What version of SQL 2005 are you using?

Secondly, if this is stored in the same places as most other Microsoft software, the setting is in the registry and it can be changed. I was part of an organization that was bought out and we had to change the registration on 3000 desktops and 120 servers. It was scripted by one of the sys admins using Powershell.

Lastly, what does this matter? This information does not appear in anything important.