Problem with WLAN connection

Hey guys, i have a TP-Link router, i've only had it since january and since about a day ago the wlan just does not connect on any of 3 pcs (2 laptops and a desktop), the wlan light blinks, it doesnt flicker it just blinks on and off, and all computers can see the SSID and can even tell me the signal strength, but just will not connect to the network, it endlsessly tells me its acquiring a network address or it's waiting for the network, and eventually it will say 'not connected' in the list of networks, but when i click on it the button down the bottom says 'Disconnect' implying it's connected? im on an ethernet cable into the very same router at the moment. Id really appreciate any help or advice, thanks in advance for your time.