Windows 2000 Professsional Slowwww Boot

I manages several small domains. Recently I upgraded a workgroup to a domain with a Windows 2000 (Dell) server. One of the clients, Windows 200 Professional, now requires 19 to 22 minutes to completely boot up. My XP clients seem a tad slow but still boot much quicker than this. My event log shows nothing that should interfere with booting and I receive no errors. Once it has booted the workstation seems fine, connectivity is staying around the 100 mark. Suggestions anyone?