Somehow I don’t have a wireless internet adapter when checking Device Manager - Network Adapter.

[RonS24319]

Probably the easiest solution is the buy a USB wireless internet adapter. My PC can access the internet via an Ethernet cable. I would prefer a way to re-install an adapter that was originally installed. 

[TheOldMan]

That PC probably came with Windows 7.  Is that still the case or has it been upgraded?

Look in Device manager to see if a wireless adapter is indicated.  If the OS is no longer Windows 7, it might just be the driver has not been installed.  If the hardware is present, it will appear under Network adapters tab.  Click on the arrow next to that category and see what is listed.  If you need help identifying possible choices, take a photo of what is listed and post it here.

[RonS24319]

Yes, my desktop was originally Win 7, but upgraded to Win 10.  In Device Manager I think there use to be a wireless internet adapter (WIA) because I could access the internet via my Netgear router, but now there isn't one.  I'm currently using a USB Dual Band + Bluetooth Adapter.  IIn your experience is it possible to install a WIA that will appear in my Device Manager so I don't need a USB WIA?  I appreciate your input.  

[TheOldMan]

In Device Manager, As posted above

If the hardware is present, it will appear under Network adapters tab. Click on the arrow next to that category and see what is listed.  If there is a Wireless adapter identified (it will say if it is wireless ) probably Realtek or Qualcomm or Intel.

As I said, take a photo or screenshot of that Network adapter area and post it, if you cannot see one listed, and I will assist further.

The original HP Pavilion Elite HPE-570t CTO Desktop PC lists wireless drivers for

Atheros Dualband Wireless Network and Ralink Wireless

If they are not showing, try the clicking on "Show hidden devices" or scan for hardware changes.

If none of that produces results, then adding an adapter is the only solution.