There is a very long thread on the MacFixit web site about stalls that last about 15-30 seconds concerning DHCP Ethernet settings in your TCP/IP control panel and/or no CD in your internal CD with Mac OS 8.6.
Try
http://www.macfixit.com/cgi-bin/ulti...i?action=intro
You may have to do some searching in the archives of the site. Try searching on the word "Stall" in the subject line.
Doug Rider