thanks wb, I have an Acer Aspire X3990 using an Intel Core i3-2120 CPU @ 3.30GHz, 64-bit OS, Windows 10 Home. I have confirmed that all drivers are up to date.
I'm not sure 82579V and 82579LM are both onboard NICs because when it reverts to 82579LM the info in Device Manager says something along the lines of 'is not currently connected' or 'not plugged in'. I'll check details more closely next time it happens.
I have noticed that the switch from 82579V to 82579LM happens after it comes back from sleep mode, and also sometimes when I turn on the computer.
I will get in touch with Acer to see if they have any suggestions and let you know if any solution is found.
thanks JFFulcrum, the description on that page sounds very much like what is happening on my computer, so I have downloaded and extracted the files, opened a command prompt as Administrator and typed in 82579VSKUW64e -nosilent as per instructions in the ReadMe.txt file but this results in the following...
82579VSKUW64e -nosilent is not recognised as an internal or expernal command, operable program or batch file
I'm not much of a DOS person so I could be doing something wrong, or alternatively is it actually possible to install in the normal way without having to do it through a command prompt? could you give me some pointers?
Update: Reading another post I learnt that I have to reference the path in the command prompt, so I did the following...
cd\Users\Pete\Downloads (press enter)
82579VSKUW64e.exe (press enter)
This action didn't provide any feedback from the command prompt, it just went back to cd\Users\Pete\Downloads>