Problem with Windows XP with SP1

Hello everyone:

In my network I have several machines with Windows XP SP1, since 5 days ago, when I want use the Remote Desktop Admin, I can?t connect to another machines. After I fill the name of the machine that I want take control, a Windows appears with the following message:

Remote Desktop Disconnected

The client could not connect to the remote computer.Remote connections migth not be enable or the computer migth be too busy to accept new connections.
It is also posible that the network problems are preventing your connections.
Please try connecting again later.

OK HELP.

My network is OK, because, I have PING to all PC?s ,also I view via “NET VIEW” all Pc?s , I apply all fixes, except SP2.

Anyone have any ideas, please.

Regards.
Fernando.