OK, let's summarize everything here: The ThinkPad now only has Ethernet connection through the NetGear Router. Wireless connection is disabled. From the ThinkPad I can browse the Internet with no problems. The 3 Pcs and ThinkPad have the same Workgroup name. All have file sharing enabled. All have s...

http://www.diplomatsoftware.com/Network2.png In this configuration I certainly only want the Ethernet Router path. So I totally disable the wireless connection. To double check, I type the command ipconfig at the command prompt on all 3 destops and the ThinkPad. All of them have the same DNS: gatew...

From the ThinkPad I don't see anywhere I can select any network path.
I also forgot to mention that the NetGear Router by itself has a hardware firewall, according to the manual.

http://www.diplomatsoftware.com/Network1.png An image is worth a thousand words. In my set up, I have 3 PCs and the ThinkPad connected to a NetGear Router through Ethernet cables. That Router is connected to AT&T 2Wire DSL Modem, which also has WiFi outside the Router. The difference I have here is...

Thanks for all your suggestions. But I did enable file sharing and even enable sharing one folder as a shared name. I did the same things on other desktop PCs with no problem, so something must be different on this ThinkPad. I tried to compare to no avail all the network settings between the ThinkPa...

I just bought a ThinkPad T60 and set it up fine with the good old Windows XP. I connect the Ethernet to a same Router in which 3 other desktop PCs are connected through a same workgroup. Internet connection works fine so there isn't any problem with the network adapter. But from the ThinkPad I canno...