You really need to remove w2k DCs correctly, and that is to dcpromo down. When you don't dcpromo down, then that leaves orphaned DCs/objects in AD, which will cause problems. Other DCs will always try to contact a DC that no longer exists, etc. In such a situation you will have to use NTDSUTIL, a w2k utility, to remove the orphaned DC from the domain. Use w2k HELP to get info on NTDSUTIL. Its a clunky utility.
The first E2k box was the first E2k server, so the Site Folders are homed there, OAB, freebusy, etc. If it no longer exists, and can't be brought up, you can use the GUIDGEN utility to reset the Site Folders on the new E2k box. If you still see the orginal E2k box in ESM, you can remove it via ADSIEDIT, in the W2k Support Tools. Path in ADSIEDIT is:
Configuration --> Services --> Microsoft Exchange --> Myexchangeorganization --> Administrative Groups --> Servers. (I think this is approximately correct).
Delete Zeus. Replicate to all DCs. But, I don't know if you should do this w/out maybe contacting MS and have them walk you through this, because your 1st W2k box, unless you manually changed things, is the fsmo role holder, schema master, infrastructure master, etc.. If you had another DC at the time when all this happened, you can SEIZE those roles w/ NTDSUTIL. I suppose you did, because you wouldnt have an AD otherwise. Basically you need to do these things:
1. Seize the fsmo roles so they are on another DC or DCs, since the 1st W2k DC is history.
2. Remove the E2k server from AD, which is relatively simple, just deleting the server object in ADSIEDIT.
3. Run GUIDGEN to reset the Site Folders. This too, relatively easy.
4. Redo all your OL profiles to point to the new E2k box, if you weren't able to move mailbox to it, and therefore enable OL clients to automatically redirect their profiles.