If the router lights appear okay but no internet, the first step is to bypass the router and attach your PC direct to the modem via cable and ensure the internet is working correctly. If that is...

Does the device you are trying to use support 5ghz as many older ones do not and even some new ones? Are you using different SSIDs? Was the 5ghz SSID used previously on that device? If so you may...

If the router does not have a scheduled reboot option (not sure why you need one) you can put a timer on the router's A/C power cord and have it power the router off and back on as desired.

Are you getting the logon page? Try http://tplinklogin.net/ in place of 192.168.0.1. Also check your modem settings to see if it want a different IP address in a field something called like Ethernet...

Another thought... Once PC-A has gone asleep, does a power down and up cycle wake it up? Then are you able to connect? If so, you could put a timer on the PC-A so it will power cycle at a set time...

Good that you are working now. Not sure either. Power down and up both the modem and router may help these unexplained things. I always power down and up the router after I have made changes so I do...