FYI: "unplugging"/turning off only SOME devices, or inthe wrong order, or not leaving them powered COMPLETELY OFF long enough is essentially the same as doing nothing.
RESETTING your network devices won't do any good unless it's done correctly:
Shutting down:
Shut down connected computer(s).
POWER OFF network devices in this order: hub/switches, then routers, then modem.
WAIT ONE FULL MINUTE.
Powering back up:
POWER ON network devices in the following order, and wait for (a given, certain) light to stop blinking steadily (or to START blinking randomly - see doc's if need be to figure out which light, or simply wait a FULL MINIUTE between each device):
Modem
WAIT
Router(s) (in outside-towards-inside order, if you have >1 router/subnet)
WAIT
hubs/switches (in any order)
Now boot up ONE computer and check it to see if everything's okay again.
NOTE: If ANY part of your setup above - except for end-node computers - loses power you should go through the entire shutdown/powerup sequence....