Probably a dumb question.  I find no model AC1900 on the website though my device is clearly marked as "TP AC1900 wireless dual band gigabit router"   This modem was supplied by my ISP who has been since bought out.  The only thing it was running (or was connected to it wirelessly) was my Insignia TV and my phone.  Neither of them can detect nor connect to the TP link router now.  The computer and my TCP/IP phone went to my old Cisco router which gets its connection via a hardwire from the back of this modem.  

I was hit by a ransomware scam.  It was unusual in that they said they would offer me "protection" for $350/year after they removed the damage.  Other telltale signs were that they would not accept a credit card, the mess that filled my screen had only their phone number appeared as a way to remedy the situation.  So they removed a lot of stuff (some of which I used almost daily), cleaned their crap (I'm guessing completely) and also changed quite a few settings.  It used to be that this computer could see the TP modem though it was not connecting wirelessly to it.  Now it can't even see the modem.  My new ISP doesn't seem to know a lot about how the equipment from the previous company they bought works.  Anyway when the scammers called and asked how the computer was working and wanting me to mail a check or buy some bitcoin I told them that it was still all fkd up and that they could go suck eggs before I would send them anything except a referral to the government agencies that are supposed to cart them off to jail.  I haven't heard a peep from them since.  Hell, I could buy a refurb computer for that much or less, but I would probably have the same problem since connection to the TP router seems to be the problem..

I've fixed/reinstalled/reset lots of stuff since then to get the computer working close to the way it used to.

So, back to the router.  This router does not have a reset button like I see in many pictures here.  I was hoping I could just reset factory settings and install as if it was new.  The main problem is that the fact that the devices (TV and phone in particular) can't see the TPLink router.  I'm only guessing that they would see it if it was reset to factory condition.

I would just connect everything to the Cisco, but after searching high and low I cannot find the password I used eons ago when I installed it.  Since the computer can't see the TP router, I can't get very far when I try to follow instructions I found on how to reset the modem through software.

So the two problems I'm stuck with are that the phone cannot connect to my home WiFi so if I use it anywhere that isn't a public WiFi I have to do it using the wireless carrier which chews up data.  And the TV can't connect to anything.

I'll appreciate any help anyone can give.