Sharepoint Login Failure

WSS 3.0
on my web front end server, domain authentication is failing with login attempts to sharepoint.  usually, the logon happens automatically using the currently logged in user's credentials.  i did windows updates on the weekend and rebooted that server. since then, i get 3 prompts to log in, and then am presented with a page stating i'm not authorized to access the sharepoint site.

this happens with any/all users attempting to log into to sharepoint on this server.
sharepoint is accessible from other computers, so it seems to be a problem with this server

but here's where the weirdness really begins:
i have 1 sharepoint site and i have it extended to 2 zones:
http://friendly_url  (zone=internet)
http://servername   (zone = default)

on this server, i can access the site with http://servername
on this server, i have the authentication failure problem with http://friendly_url

event viewer records a login failure
Logon Failure:
       Reason:            An error occurred during logon
       User Name:      username
       Domain:            domainname
       Logon Type:      3
       Logon Process:      ÈùÐ  
       Authentication Package:      NTLM
       Workstation Name:      SERVERNAME
       Status code:      0xC000006D
       Substatus code:      0x0
       Caller User Name:      -
       Caller Domain:      -
       Caller Logon ID:      -
       Caller Process ID:      -
       Transited Services:      -
       Source Network Address:      <IP Address of web front end server>
       Source Port:      4447