Thanks to everyone who provided leads on my problem. They were appreciated and kept me searching for a solution where on my own I probably would have given up. I thought I would update the thread here for anyone who might come upon it with Internet search. The symptoms were accurately reported, but ...

I have multiple 2504s and both run fine on my T60p and Z61t. Would you be able to give us some more information? - has it always behaved like this ~ if not, when did it start occurring and were any major changes done to the laptop during that period (i.e. OS / BIOS / hardware changes) - does the W5...

I realize this thread is old, but I am wondering if the creator ever found any solution. I believe I have the same problem with this minidock with a W500. The OS (both Windows 7 and Windows 10) repeatedly hangs when the dock's ethernet is connected. It took a lot to narrow it down to this connection...