This is a post that is better suited for a Windows 2000 or Active Directory specfic forum(s).
I can tell you that the introdcution of AD (Active Directory) services causes a huge increase in complexity and system overhead, and a corresponding increase in startup time is to be expected. Honestly, the 5-10 minutes that you listed is not all that bad - I've got a 500Mhz 512mb Win2K test server with AD that is a pretty bare bones setup and it takes at least 10 minutes to startup on a cold boot.
The main thing here is whether or not you need AD services running on that system. If so, you can spend time making minor tweaks that may save you a minute or so, but overall you will have to live with the increase in startup time.
Chad D. Stiller, MCSE
Ramcom Technology
cds@ramcom.com