I am 84 years old and my brain is struggling with prescription medications so nothing makes sense to me!

I installed the Archer C7 in sept. 2016 and have to state this is the most reliable router I have ever had, including the fact it covers my 2 story house great and I retired 2 repeaters.
Lately we have lost our cable internet usage. Each time I called Comcast they said there have been no outages in my area and went through unplugging the Arris SB6141, then the router and lo ad behold everything is working great. We only use Comcast for the internet and OOMA telephone., we have been with Dish TV for close to 20 years and will be forever!
Recently, sometime we loose the Comcast signal 2 or 3 times in the evening, which is when my wife makes her hour or 2 calls to the family. This morning she explained to me she lost the telephone while she was making calls.
The appropriate modem lights are on or blinking normally when these failures occur. I was confused about the router lights so right now I don't know what they have been doing. I put a sticker on the internet light so I will look at it in the future.
This morning, when there was no signal I moved the router plug to a dedicated power bar so I could use the switch to shut off the router power so my wife could shut off the route power, wait 10 seconds to switch it back on in case I am not available.

My confusion is, how do I know whether the signal is coming through the modem? I don't know if I should get a spare modem or a spare router or if Comcast is off!

By the way, starting a few days ago I cannot print from this desktop to the Brother all in one, even when I switched to wireless. My wife's desktop can print either way and the 2 desktops and printer are in the same room.

I need a nap!!!