Ping myself, works with ipv6 not ipv4 in Windows 7

Solution 1:

By default the Windows 7 firewall is configured to not respond to ping requests. You can change this behavior by following tutorials like this by Sysprobs.com.

You can additionally verify that Network Discovery and File and Printer Sharing are turned on (Control Panel\All Control Panel Items\Network and Sharing Center\Advanced sharing settings).

Solution 2:

The strange behaviour disappeared after I uninstalled all my VPN clients (I'm working for different customers).

One of these "clients" was probably "something more" then just a client and blocked my computer from the incoming ping calls.

After uninstallation everything works as intended. Time to start installing all these VPN clients on a virtual computer:)

Thanks everyone for your great feedback. As usual, I was the weakest link, not the hardware/software:)