exchange server beta

Hi,

I have found out that the exchange server that we have installed in our network is a beta version. This beta version (exchange 2000) just expired and now every hour the services stop. I have the license and the software, the only thing is that when i try to reinstall it in the server where i have the beta it says “error checking prerequisites… there is no such object in the server”
My question is, what should i do? can i install another exchange server in the network (temporary exchange) and then rebuild the original one? can i replace the beta for a full version without problem of loosing the mailbox?

Any advice on how to procee is welcome

thanks