For about the past week or so, some of my contacts are shown "Offline" when I know they're not. And it shows me offline on their account. And we can't figure out what is going on. It's a total of about 20 contacts maybe.

We've tried deleting each other and re-adding, and blocking/unblocking, rebooting. Nothing is working. It just shows people offline.

Someone said that it had my MSN ( asterisk@akfg.net ) registered under two emails, so I checked under live.com and it's only registered to the one above. So I don't know what to do now.

Well, since you can send offline messages with Windows Live Messenger, I'd try that. Hopefully, eventually, the two clients should realize that they're online once you start sending messages. I've had similar problems with MSN, and it sucks. Also try allowing all to contact you in the settings.

Offline messengering doesn't work, we can't read it.

how about logging in with other pcs's eg internet cafe? that will tell you if its a problem with your client/pc/connection or your account etc.

I guess it's my account, I just tried logging into my dad's computer and it's the same thing.

Normally I'd have about 50 people online, now I have about 10. It's getting worse everyday, I don't know what's happening..

try a few things.. although these are just guesses

try http://webmessenger.msn.com/
try cleaning out your contacts.. maybe it can't handle too much on one account..
if it gets desperate, create a new account and add your friends to it, leave the other one with a nick to say "new msn address ....@hotmail..."

How can I delete all my contacts without right clicking each single contact and click "Delete contact".

i don't even know if thats possible.. sorry...