TeamViewer is a great suggestion, but it isn't the question.
Plus RDC is better than any other remote software.
koby has a good point:
Enter computer name under computer in General section.
You don't even need your user name, but if you do, just use Karima. Try it without.
Under edit, go ahead and enter your username and the password of the machine you are trying to reach if it is password protected.
Since using IP, do an ipconfig to ensure you are using the correct one.
Can you ping the machine? Can it ping yours?
Can you access shares on the machine. If not, then it will not connect.
Turn off A/V (doubtful)
Remember, everyone, he can access other machines, so it shouldn't be firewall or A/V. Won't hurt to put port TCP and UDP 3389 and browse to RDC.
