Your firewall on the pc's wont need to be turned off.

Are you connecting in AP mode (like the v4 came) or have you put the V4 on your wifi network?

Can you be more specific? Are you having trouble connecting in ARC itself or are you having trouble connecting to your EZB via Wifi (AP mode...) on your pc?

I see EZ-B on my wifi list and when I click connect it says it can't. No problem on my lap top but neither of my desk tops will connect.

What make and model are the desktops ? What WiFi hardware is installed?

One is a Gateway DX4860-US20P with built in WIFI. Windows 7 home premium 64 bit. The other is a ZT what ever that is and running Windows 7 home premium 64 bit. This one has a WIFI adapter.

And other WiFi connections can be accomplished on the two desktops ?

I connect to the internet okay.

From your posts it seems that your trying to connect through your home network router? Is that correct? If not are you trying to connect using the default AP mode? If through your home network router. Have you tried to assign a static IP address to your EZB and all your computers in your router's setup menu? This may not help with your problem as it does sound like you can connect your one laptop to EZB but it will allow the router to find all your computers much more efficiently and quickly.

I'm no router expert and there are others here that know that realm better then I but I had to buy a newer home network router to get my connections to stick. I also had to assign static IP's to all my devices to make things work flawlessly. Right now I have two EZB v4's in my robot and they connect through my home network router to ARC every time with no disconnects. Also in your router menu have you tried to release and/or renew your IP list? Give that a try.

Here's a thread from when I was setting up my multi V4 EZB robot which hopefully might help:

Connecting To Two V4 Ezb's