I tried everything that they talk about in this page. None of it works. This Del Inspiron 570 actually had been scrapped and put to the side marked with a bad motherboard tag.
The computer kept either shutting down or rebooting or it seemed to go into a sleep mode you could not wake it from. After I got my first Blue Screen error I realized it was a driver conflict with the newer Windows 7 - 64 bit. I found the right driver and now the machine that was being tossed is being used by one of the managers. All it was, is that it needed the right drivers. The video driver on dells site is good and so is the audio and/or chipset but the network driver does not work. I looked for the Broadcom NetLink Gigabit Driver and I found it at Intel's website. Now the machine works great.
For anyone else having this problem, I think I have it figured out. It seems the correct driver IS in R243218. However, it does not seem to detect it because the Northbridge driver is not loaded. I had a newer AMD video card installed, and downloaded and installed the newest driver for it, but it did not include the Northbridge driver. The chipset driver found earlier in this thread has it. Once that driver is installed, you can update the driver by navigating to the specific folder for your OS in the extracted R243218 folder.
None of the drivers at Dell work for the Network card. Found correct driver at Intel's website. LAN: Broadcom* NetLink Gigabit Ethernet Driver. Inspiron 570 Ethernet Controller Driver Missing. For anyone else having this problem, I think I have it figured out. It seems the correct driver IS in R243218.
I did it twice and it worked both times.