Question : Windows server 2003

Hi we have 2 Win2k3 standalone servers (not AD), with about 100 users. 1 server is an application server and the other is an access database and file sharing server. users  install the application and the database on their local machine and it's all mapped to the servers. We have about 25 RDC users also that use these 2 servers. I hear alot of talk about Active Directory, but i don't see a good reason why we need to switch to a domain controller setup when the setup we have now seems to work great. any advice on what and how to decide what to do.

Answer : Windows server 2003

On which?  The non application of the GPO when the DC is disconnected from the network?

On point for your issue:
http://serverfault.com/questions/48144/lock-workstation-glitch-ad-windows-xp