I am having a strange problem with my Dell Vostro 1500 running Windows 7 Professional on my home network. I connect using wireless using the built-in Dell 1490 wireless adapter updated to the latest Dell drivers. I actually have two of these machines, nearly identical except that the other has Windows 7 Home. It does NOT have this same problem.
I have no issues with my wireless connection to my Belkin Router. I have a very strong signal and have never had any Internet connectivity issues over wireless from this machine. The problem is that when I try to connect over the LAN, I cannot connect to anything.
Both my Dell laptops are connected to the Belkin router wireless. I also have an Epson Artisan 810 printer network connected via a wired cable. The Dell Vostro 1500 running W7Pro will not connect to the printer, and I cannot connect to the other Dell Vostro's shared folders when using the wireless connection. If I disable wireless and plug in a network cable to my Dell Vostro 1500, I CAN print without issue and I can browse to the other Vostro's shared folders.
When I wireless, if I ping the printer's IP address I get 3 no responses and the 4th ping returns a response in <1ms, for a 75% packet loss. If I connect that same machine to the wired network cable I can ping the printer's IP address without issue with 0% packet loss.
Both Dell laptops both have the Dell 1490 wireless adapter.
I don't know for sure if this is the problem, but if the router has a wireless option called "AP Isolation", make sure it's disabled.
AP Isolation prevents wireless devices from communicating w/ each other. It's a security feature available w/ some routers. However, they can still communicate w/ any wired devices. And that's why I'm not sure. Although AP Isolation seems consistent w/ your communications problems between the laptops, it's NOT consistent w/ your wired printer. I suppose it’s possible it’s not just one thing causing all the problems. Maybe the wireless laptops can’t communicate w/ each other due to AP Isolation, but the printer is a completely different problem.
Anyway, it’s easy enough to just check the router’s wireless section, see if there’s an AP Isolation option, and make sure it’s disabled. Then work from there.