Remote Desktop does’nt work over internet

Hey guys,

-windows xp
-edimax router
-dyndns
-kaspersky anti-virus

I have a very annoying problem with RDP, I’m able to access my computer from the LAN fine but when I try to connect from the internet it say’s that my user/password is’nt currect.

obviously you can guess that the port forwarding is working fine from my router since i get the login screen.
also, remote desktop suppose to work fine since it work’s when the connection is coming from inside the LAN.

What am I doing wrong ? I’m sure whatever solve’s this would make me feel dumb hehe..but I’m willing to accept it if I could just make this work :)~

Thanks alot in advance !