Cannot access admin area and MU is all messed up

Hey Guys,
I was wondering if any of ever had this happen.

I was getting ready to upgrade one of my WPMU instals to wordpress3.
But I have found that when I try to login even with the correct password it sends me back to login screen and I cannot get past it.

Also all of the blogs in this install get redirected to one specific blog.

Not really sure what to do about this.