-Ralph-

OK, if you can ping google via the wireless on your laptop, the laptop is not blocking anything, more likely the router is not responding to ping.

Just to be sure on the advanced tab on your laptop windows firewall settings, untick "wireless network connection" and click OK, then try

ping 192.168.2.1

again while connected via wireless, then if it makes a difference tell me and we'll dig into advanced windows firewall settings, but since you can ping google I think it won't make a difference. Don't forget to tick it again afterwards.

Now lets see if since you can ping google, if you can ping the desktop PC, not being able ping the gateway address may just have been a red herring because the gateway address, which belongs to the router, is not responding.

On the desktop go to a commmand prompt (black window where you type ping commands) and type

ipconfig

then find the IP address of the desktop machine here

Ethernet adapter Local Area Connection:

Connection-specific DNS Suffix . :
Link-local IPv6 Address . . . . . :
IPv4 Address. . . . . . . . . . . : 192.168.2.x
Subnet Mask . . . . . . . . . . . :
Default Gateway . . . . . . . . . :

then on the laptop connected via the wireless type

ping 192.168.2.x

where x is the number you found in the ipconfig

Let me know the result, if it doesn't work, the problem lies with your router.