Check posts on other boards. You may already have a 2k that works, and may not work after installing sp4. I know I did. And I have no intention of letting sp4 near my rig again until M$ figures out why it hosed my (and many other) perfectly working systems.
It's your call....it's your gear.
Please don't ask for help. Just re-format and re-install and call it an education.
As the man told me.....some times it's just your day to be \"it\".
Good luck with your newly-installed system. I'll bet it runs better.