Problem With Teracom Tdsl300w2 Router

I have just registered on the forum as I have problem with my router and I am hoping I would get some help in solving the problem. The router which I am using is a Wireless Teracom TDSL300W2. Now the problem is that the router works fine when I connect a LAN Ethernet cable but it doesn't work on wifi, I have set the router up correctly according to the instructions but I don't know what the problem is.