|What you have not done is determine whether the problem is isolated to the PC, the Router or your Modem.|
Do you have more than one client system running off the router? If re-booting the router does not help how about re-booting the PC ?
EG in my own home network I have a cable modem attached to Router ( 4 port LAN + wireless) then an 8 port switch with a bunch of PCs and other devices.
At various times the wireless will drop out and re-booting the router is all it takes to fix the problem, but the wireless PCs often need to be rebooted after the router.
Sometimes it is the wired systems that drop out ( the switch glitches). Re-booting only the switch does not always restore connectivity.
The best method is to turn everything off. Then boot each device in order beginning with the Modem followed by router then switch then wired & wireless PCs waiting a minute or so between each device.
Goin' Fishin' (Some day)