laptop max 100 Mbps only on COX 150 Mbps plan

Did troubleshooting update the drivers of your NIC?  You can get the make and model of your NIC via the same run command and research...or post.  If no drivers available, you could disable then re-enable...then uninstall then re-install...the NIC.

I don't think manufacturers have sold Fast Ethernet computers in decades.

thanks for the suggestions.

running the troubleshoot came back with no issues and it did not have to update my NIC drivers. I do not think I want to uninstall that NIC driver at this time, may lead to other issues - such as not able to find / download / install the correct driver.

The Dell Support Assist software broke and is no longer able to run, so it is no longer able to update my drivers.

see reply above - my modem/router works at 150 Mbps. I have a company laptop that is able to go above 100 Mbps. It is only my own Dell laptop that is limited to 100 Mbps. Also if I use 5 GHz Wifi, I am able to get over 100 Mbps. So it is definitely the NIC card in my own Dell laptop that seems to be the issue.

How to check ethernet adapter speed in Control Panel

Press Windows Key + R and type control panel. Click OK to open the Control Panel.

Windows 10

1. Open Control Panel.
2. Click on Network and Internet.
3. Click on Network and Sharing Center.
4. Click on Change adapter settings.
5. Double-click the network adapter.
6. Check the connection speed in the Speed field.

Windows 7

1. Open Control Panel.
2. Click on Network and Internet.
3. Click on View network status and tasks.
4. Click on Change adapter settings.
5. Double-click the Local Area Connection.
6. Check the connection speed in the Speed field.

If the ethernet adapter speed is 100 Mbps, you will be limited to a download speed less than 100 Mbps, regardless of the download speed provided by Cox. 

I do not think I want to uninstall that NIC driver at this time, may lead to other issues

It's a "soft" uninstall.  The drivers will remain on your computer.  You just uninstall the NIC and then reinstall.

Doesn't look like Win10 dialog boxes.

It looks like your ethernet adapter (NIC) is the limiting factor.  In addition to the 100 Mbps speed in network adapter settings, the FE in the description is further evidence.  I recently replaced my NIC with a Realtek PCIe GBE Family Controller that adapter settings show 1.0 Gbps speed. 

Thanks everyone for the help.

Now that I at least know the NIC is the limiting factor, I will have to determine my next step.

And one of that is definitely to decline Cox offer to upgrade my speed 🙂

Thanks.

So you never measured 100 Mbps on this PC?

Is your NIC really a "limiting factor"?  What would you do on this PC requiring more than 100 Mbps?

You only started this post because your NIC read "100 Mbps" but not because you weren't getting enough bandwidth.

The OP never reached 100 Mbps on this laptop and certainly not the 300 Mbps he said he thought he’d seen.   I think he probably posted because speed tests reported a slower download speed than what he thought he used to get.  But he later posted that maybe he was using a different laptop back then.  We know that he would absolutely have had to use a different laptop for 300 Mbps download.  As I indicated in a different thread, there’s nothing you can do at 300 Mbps that you can’t do at 94 Mbps except download large files faster.  A 100 Mbps NIC doesn’t limit what you can do (except for the large file thing), but… it does limit download speed to under 100 Mbps, so it is a “limiting factor”.  It’s just not one that’s normally going to be noticeable when browsing, using email or streaming.