Is it possible to deny or prevent or obstruct a network scan on the network where your computer is connected to?
If you don't want your pc to be scanned for open ports or available services, you can use a firewall that closes/stealths the necessary ports. Beware, certain ports wil always be open to be able to communicate with the network.
First, go to Start Menu->Run window. Type
This command will hide you from the Network neighborhood but your shared folders can still be access.
Note: in Windows Vista, you need to open the command Prompt as Administrator: Start Menu > type
or else you’ll get this message:
So how about my IP address? what if they have an ip-scanner, still they can find me?
They can find you by using an ipscanner. The solution for this problem is by using a Firewall. Upgrade to Windows XP Service Pack 2, there is a free inbound protection firewall. For Windows Vista users, there is an inbound and outbound firewall protection by default.
To check if your computer is hidden in the network neighborhood type this in the command prompt:
How to Show your Computer Again inside the Network Neighborhood
Note: It only works for windows xp sp2 and up use as admin and open cmd as admin if you can still be found update your pc and install a good firewall like Zone Alarm-Firewall.