Please read this post, do not close it refering myself and others to go to http://ideas.live.com, there are no answers there.
There have been a huge increase in requests for help about 8.0 and why the product freezes up at sign-in.
There is a problem, please advise as to what action to take or an actual "Knowledge Database Number" to asist with the fix as there doesn't seem to be any info.
I have come across 200 requests for assistance to this point in the past 24 hours.
Please tell somebody!!

Messenger Live Beta 8.0 Frozen
DazlerD
Try more general help and support options instead
http://forums.microsoft.com/MSDN/ShowPost.aspx PostID=368260&SiteID=1
http://forums.microsoft.com/MSDN/ShowPost.aspx PostID=335030&SiteID=1