The support guys over at OCZ had the same problem as you/I. The only thing that got the k8n neo2 to boot again was:

1. Shut off the PSU
2. Disconnect all power cables, all drives, everything...
3. Remove the BIOS battery
4. Shorten the two batterypins with something metal *duh*
5. Wait a couple of minutes
6. Reconnect everything and try.

This worked for me, I got the PowerStream to work with my k8n neo2 again. But it didn't last long, few days later my mobo was totally dead!!

I'm so f***ing mad at MSI not to go public with this problem! But the funniest thing was when I got my Abit AV8. They didn't even tell on their homepage that winchesters wouldn't work with BIOS older than version 1.5. Had to do a hotswap flash with my old NF7S V2. I'm starting to think that the socket 939 is all a joke! I've never ever in my whole life experienced a socket relase with so many problems.

//Over and out