My old computer crashed, i had an old version of live on there.. I got on a new computer installed the newest live version and signed it, it had my screen name but none of my contacts and everytime i tried to add a contact it says that they do not have messenger, and they do, can anyone help me please?
I have cleared the cache from here : \Documents and Settings\<account>\Local Settings\Application Data\Microsoft\Windows Live Contacts\ and restarted it. I still have the problem.

I presume you posted this in Messenger Plus! Help & Support by accident, as it's not related to Plus!

Think of anything that could be causing this? Add-ons, patches, firewall, etc.? Remove/turn-off all of them.

Try removing Messenger (with ZapMessenger) or 'Repairing Messenger' if you have Plus! installed, via Add/Remove Programs.

Only other thing I can think of is doing a clean install. Follow these instructions.