Not sure what the problem is but sounds like the radio just went dead. Ditch the router if it's old and get one of those new 802.11AC routers. It's backwards compatible with all the older standards and they operate on both 5Ghz channel (so less interference) alongside 2.4Ghz are super fast approaching gigabit speeds over air. With the "ac" standard, these routers can perform something called "beamforming" on 5Ghz channel (if supported) which is identify where your wireless devices are and concentrate the signal more towards that direction rather than just blanket transmitting everywhere.
I recently upgraded from an aging 802.11N D-Link "Gamefuel" router:
to this Netgear 802.11AC1900 "Nighthawk" router:
Couldn't be much happier. No deadspots, super wide range covering the entire house and yard two SSID channels for 2.4ghz/5ghz + guest access. Lots of tweaks and settings, 2 USB 2.0 ports, 1 USB 3.0 port and 1Ghz dual core ARM processor which is unheard of in a router. Also does beamforming as I mentioned above but has something Netgear calls "Beamforming+" which can do this also on the standard 2.4Ghz channels alongside 5Ghz. Streams 1080P HD from home server at high bitrate no problems over the air to all our devices - phones, tablets, mobile game devices. House is already wired up with hard line gigabit but the Wi-Fi was getting old, interference and all.
Theoretical limits for wireless standards quote from speedguide.net:
802.11b - 11
Mbps (2.4GHz)
802.11a - 54
Mbps (5 GHz)
802.11g - 54
Mbps (2.4GHz)
802.11n - 600
Mbps (2.4GHz and 5 GHz) - 150Mbps typical for network adapters, 300Mbps, 450Mbps, and 600Mbps speeds when
bonding channels with some routers
802.11ac - 1300
Mbps (5 GHz) - new standard that uses wider channels,
QAM and spatial streams for higher
throughput