You need to enable password on the account that you want to access remotley. Without that it won't work. Click on start- then click on your account name/icon (top left corner)-click on "home" and then click on your account. You will see field to change or set your password.
Then you need to enable remote desktop on that account. Right click "My Computer"- go to "Properties"- Click "remote" tab. Check box that says "Allow users to connect remotley this computer"
Next thing you will need is that IP of your PC (that is if you don't have a router between your pc and modem)
Click start-run- type cmd, on the dos prompt type ipconfig
You will see your IP address. Write it down.
On your remote pc ( that one that you're on right now) go to Start-all programs-connections-remote desktop connections.
Enter the IP that you have written down and you should be good to go.