Event ID 15016 — HTTP Service Authentication/please HELP!

Hi,

I'm running VIsta Ultimate with Service Pack-1 and most of the times my PC
does not boot until I push the reset button, then it does boot and when
checking: >> Event Viewer>> System, there is a red marked Error event that
reads: "Unable to initialize the security package Kerberos for server side
authentication"

I'm on a wired network with broadband Internet connection (cable) with a
Netgear RangeMax router, I have another 2 PCs running Vista Ultimate and
Windows XP-Pro running without problems on the same network.

I have tried turning off the Windows Firewall and changing several of my
Sharing settings but the problem still there.....

I'll appreciate any help regarding how to solve this problem.

My system:
Asus P5K Premium Black Pearl Edition motherboard.
Intel Core-2 Extreme Q6850 / 4GB RAM
ATI Radeon HD2600XT video card.

Thanks in advance,
Willy