Windows 7 windows 7 and windows 2000

hi, i need to send a file from win7 mount on a lenovo thinkpad to a desktop with win2000 throught lan cable, but i can't see desktop pc in my laptop.
In conclusion:

FROM DESKTOP WIN2000------SEND FILE--------TO LAPTOP WIN7 OK
LAPTOP WIN 7------SEND FILE--------TO DESKTOP WIN2000 NOT OK

(all win7's protections are disactivate and i upgrade win 2000 until sp4)

what can i do?

thx,bye.

What if you try a folder instead of the desktop.

for desktop i mean the win2000's machine not the path.