Win 2k Pro Problem.

I have a Laptop, recently installed win2kPro. But Today morning it stopped Printing to network printers, cannot ping any of the computers on the network. But can connect to Lotus Mails Server. Inetnet Browsing which is through Proxy server is also Happening can telnet my Sun Server.
It doesn’t have any service Pack Installed.

Can Some one help Pls.