Going in to the control panel finding the NIC is not so bad. But then you must google the model and sort through that rats nest of results. Say I run a speed test on my laptop and the results are 156 Mbps, customer sees maybe 25 wireless and maybe 75 wired. Just one of those things you run into every now and then working with customers.

Do they leave all of their network devices on when they're not being used? I ran speed tests when a customer complained of slow speeds and found that all of hers were on. As soon as I turned most of them off, the speed improved and I could consistently ping her computer. When they were still on, most pings were unsuccessful, losing at least half of the and with long delays/time outs. My laptop worked fine on her network with Firefox and Explorer, hers was only good with Explorer.

Look in Task Manager, Applications, Processes and Networking for more info- if you see applications that aren't responding and/or are hogging resources, try shutting them off if they aren't needed.

How old is their computer?

"Speccy" is a great little program to show what's going on in a PC.
Software, CPU, Ram, Drives, Cards, Network, etc...

[Link: piriform.com]

Thanks for the replies. I will put them to use on the next encounter. Not going back on the one that prompted me to ask this question.