Connectivity problem - modem diagnostic

[alwann]

My desktop machine keeps losing its internet connection. Rebooting the computer and the modem re-establishes the connection. When off-line, I've run a diagnostic that always indicates the Ethernet cable is disconnected, but of course that is not the case.

I'm running Windows 10 with Comcast. No problem with Comcast signal on my other devices

The connection tends to drop when the machine has been sitting idle for several hours, or over night.

I recently updated my PC tune-up and security software and wonder if doing this might have affected some option.

Also, let me ask if there is a way to check whether the modem is failing? It's four-years-old.

Thanks in advance for all advice.

[petsetc]

I had similar problem. Tracked down to USB 3 devices interfering with 2.4GHz. I bought a 5Ghz dongle, got a longer USB 3 cable to move the USB 3 devices about 3 ft away from laptop, solved ALL my issues. Hope that might help.