I own a Dell N7110 laptop, which had been working perfectly until a while ago. At some stage, between updating to Win 8.1 and applying a Bios update, a vet peculiar thing happened. A number of peripheral devices simply disappeared from device manager, and do not work.
These include the wifi and NIC adapters and both USB 3 ports. Thankfully, the single USB 2 port still works, so I've inserted a wifi dongle to continue working.
To be clear, these devices DO NOT appear in device manager with the yellow exclamation mark against them - them simply do not appear whatsoever. I've tried downloading all sorts of drivers, and reverting to earlier BIos versions, and even going back to the originally supplied Win 7 disk, but to no avail.
What am I doing wrong here, guys? Any help gratefully received. Thanks in advance.