computer centre had blocked port 1433 and 1434. if you wanna connect, do the following:
1.Start menu -> SQL Server -> Client Network Utilities
2.Tab Alias -> Add
3.Server Alias: anyname you like, say serversql
Network Libraries: TCP/IP
Server Name: (specify you sql server name here)
Uncheck "Dynamically determine port", and specify the port (use a very large number say 66666, u hv also to configure the server side 66666)
4. Click OK
Next Go to SQL Enterprise Manager, Register for a new server
Server: serversql (the alias name you have choosen)
UserID: xxxxx
Password: ******

done.