Windows 7: Remote Desktop Connection Fails

I want to access to my laptop which is in another room via my wireless home network.



IP of PC: 192.168.1.2 (Windows 7 Ultimate)
IP of Laptop: 192.168.1.5 (Windows XP Home SP3)



I get this error message:


However,
1) Relevant "Remote Access" services are running on both machines. I don't know if there is another way of enabling it.
2) Both computers are on and running.
3) Both computers are under the same wireless modem. I can send and receive files between these two computers via their shared folders.

I left the "User name" field empty in the screenshot above, but nothing change even if I write the user name.

What am I missing?

If you look in this tutorial there is an option to allow for remote desktop between different Op systems. Do you have that one checked off? Your A/V software can also cause these types of problems to occur.

Remote Desktop Connection (RDC) - Network

^ I clicked that check box in both machines, but it is still the same.