Desktop PC networking mystery

Factual Questions
1

A computer in another room used by my aunt lost network connectivity recently (Comcast/Xfinity Ethernet and WiFi access point via USB Network adapter dongle.) FYI, but not relevant <I think> is that this PC was one of many things zapped by a lightning surge; everything else I replaced but this PC was repaired. This PC worked fine for four months (Solitaire & webmail only mostly), but now can no longer connect to the internet.

Troubleshooter gives a message that says ethernet cable is not connected or broken. Wireless adapter doesn’t seem to be recognized at all. I tested the ethernet cable in my room with my PC – worked fine. Took my PC and cable into the other room – worked fine. Took “problem” PC to my room – worked fine!

Any ideas?

2

A recent Windows update bollixed network access.

3

Thanks for that, unfortunately it didn’t fix my problem.

4

Could be a broken device driver entry. Try the steps I gave in post 7 of this thread:
http://boards.straightdope.com/sdmb/showthread.php?t=812103

5

Step 1 : confirm that the USB port you are using works (plug in some other device/USB-drive)
Step 2 : confirm the wifi is working (check with your phone or something)
Step 3 : confirm the USB dongle is working (plug it into another computer)

If you have confirmed these things you should start looking at drivers.

6

What was “repaired” on it?? What was replaced?

If it can’t see the wireless dongle at all, that could be a defective dongle, or a defective USB port.

If the problem PC worked in another room, it could have an intermittent problem, which could be any of the elements involved (motherboard, dongle, cable), or it could be that you haven’t recognized the entire list of items you moved and didn’t move, in order to test it in the other room. And of course, network cables can be intermittent in subtle ways such that they will work in one machine, and not another.

I’ve never seen drivers have anything to do with failure to even SEE something electrically, so I have doubts about that as a solution. But of course, making sure your drivers are up to date and not corrupted, never hurts.

7

The OP didn’t describe the problem in exactly that way. A broken device driver absolutely can result in a computer appearing to fail to acknowledge the presence of a hardware device. In cases like that, unless you’re watching in Device Manager, it may appear that nothing at all is happening.

Of course, it might be faulty hardware, including the dongle, the USB port or the motherboard.