Hi, I take it you mean just the WIN2k server name and not the Exhange org name or site name. Well first of all there are many ways, but I found the safest way would be to back a full backup of your exchange server to tape or copy somewhere, (MDBDATA, DSADATA, MTADATA folders), run Exchange optimizer and note down every location here. Take the old server off the network and remove the server name from the domain too. You need to then run up the Win2k server with the same way as your NT 4 server, so same partitions, server name and put the IP in to. Put Exchange in the same loctions basically, so if it was on the c: put in on the c: of the new server. When installing Exchange make sure you choose the same org name and site name, once Exchange is installed run optimizer again and move the databases to the same as the old server. Install SP4 for exchange, and check you can load Exchange Admin. Go to every mdbdata, dsadata and mta folder and create a backup folder and put the contents of those folders into each backup folder. Now copy or from backup put the files into the relevent folders. Once this is done start the services one by one. If you get an error like Event id 1011 when stating IMS then go to a command prompt and goto <drive>:\Exchsrvr\bin and run isinteg -patch and a success message sgould appear. Now try run it.
Hope this helps
ANdy