Accessing Sql server management 2005 data from local machine

I want to access data from sql server 2005 from my local machine i.e from different ip address.

I tried to access using 'Ip/Instance' eg "10.10.10.10/Myinstance" and with userid and password but not able to access it.

getting error --enter image description here

I read earlier that we need to register local Ip in 'sql server configuration manager', but i forget it.

or If you have solution please tell me.

thanks and regards
sagar