Does anyone know how to find out what is blocking incoming ping requests?

I have a laptop I'm trying to connect to remotely and I can ping out of it to any PC on my network but no PC can ping back into it. There's no IPsec policy installed and all firewalls are turned off. Any ideas as to what might block incoming requests?

What is a VPN?

VPN is (Virtual Private Network) were first used by companies to enable their employees to securely access internal systems such as email remotely (e.g. from home or while on business trips). Today they are increasingly being used for personal use by individuals to protect their privacy while online in public places (e.g. when using the wi-fi connection in a cafe) or in a country where the internet is censored / blocked (e.g. China, Saudi Arabia��).