Those devices you uninstalled in Device Manager, including the 'Fast Ethernet Device', will simply re-appear the next time you start Windows because the physical devices they refer to are still fitted inside the PC. All you've 'uninstalled' is the entry for it.
Windows always checks the system for 'new hardware'(even though it isn't new to you) when it starts, and any it detects it then proceeds to install it's driver (that's what you see in 'device manager') or labels it as "Unknown Device" if a suitable driver is not on the system. To prevent Windows putting that entry back you would have to open the system case and pull out the device.
Personally I would leave the Ethernet card in place and just 'disable' it as you did previously. It isn't do any harm in there, and if it should be needed in the future all you need to do is "enable" it again, which is much quicker than having to find it and fit it.
On a final note, your existing cable-modem probably doesn't have an ethernet port. But check just to be sure as some have both USB & Ethernet. If it does have one, that method of connection is more reliable than USB in this instance. You won't need to install a driver (that's only needed for USB) either so no chance of getting a driver problem such as it conflicting with another driver now or in the future. The fewer drivers you need to install the better, and using ethernet for your internet access is one way of achieving that.
Edited by pip22, 12 February 2007 - 09:43 AM.