Re: AIM problem
 

Theres a lot of places where you can have a problem here,

• Internet Service Provider
• Firewall
• Networking issues, (if your using windows xp try the repair network tool)
• Your Client (http://en.wikipedia.org/wiki/Compari...ant_messengers)
• Your screen name (restarting the app may do the trick, or as bharat said a new screen name may fix it)
• maybe its your computer (restart!)
• Spyware/Virus (Spybot/Adaware)

As you can see theres a lot of places where it can go wrong, so just guess and check it'll iron out eventually