How can i block remote computer local or internet traffic? my Os - windows XP, which is the best program for that purpose
Depending on the type of internet traffic you want to block, you may get away with some routing table changes.
If you remove the default gateway setting from your Windows XP, nobody from outside of your network segment will be able to reach you. They may be able to send you a packet, but since you have no route to the host to reply, there cannot be any actual internet connection.
But doing this also prevents you from reaching those IP addresses as well. You are actually cutting yourself off the rest of the internet, but not from the computer on your local network segment. Routing can be complex.
If you only want to block incoming network traffic, you can install a local firewall, such as those from Symantec, McAfee, etc. There are free ones too. Those will let you surf the net, but not others connect to you. Those firewalls will let you block traffic based on the port, the source IP address/network, time of day, etc.
The most brutal way to do it is to simply disable your network card (or just unplug the cable). But I don't think this is what you intend to do.