OK guys so I noticed that there are lots of people who seem to be having this same problem logging into the new Windows Live Messenger, This is the method to fix ERROR : 8100030d
If you do your research on the Internet, you will see that Microsoft gives you a method to fix the following error, and kudos to them for their effort. Unfortunately this method is wrong and does not help.
This way is quick effective and I have never ever heard of any side problems, or anything of the sort.
This is the fix for Windows Vista, I am not aware or sure if this works with windows XP; but you could try. Alternately some things would probably be different.
Step 1: Registry Values
> Windows live contacts
> Database .
Once You Get To This Point Your Almost Done, All Your Going To Have To Do Is Delete 2 Files:
C:\Users\ Your Windows logon name \Contacts\ Your Messenger e-mail address
C:\Users\ Your Windows logon name \Contacts\ Your Messenger e-mail address \ shadow
*[[Basically The 2 Writen With Your e-mail Adress
Step 2: CONGRATS!