Can't login

I CAN login to Linux SSH server via WinSCP from SOME machines, but not from some others.
There is no firewall on the client side and the client machine is pretty quick (3,6GHz). Fresh WindowsXP SP2 instalation and NO other programs.
Even PUTTY gets absolutely NO response.

What should I do?

Thanks.

Even SecureCRT doesn't connect and doesn't create log file. It has probably NO response in the same way as PuTTY.

I suspect the Intel LAN card on the board....even if the card works fine on internet.

If you have fresh WindowsXP SP2 instalation, then you probably have also firewall on. Try to turn it off.

As I have found, the server accepts only registered IP address.