What I would do is remove your DSL router program, turn off the computer and turn on and reinstall program CD-DVD. Next Plug back in your DSL router, turn on you router and see if it starts working. If not then push in the reset button(sometimes hidden behind a very tiny hole so you have to use a paper clip or the tip of a pen to push the reset button.
If that doesn't wrork you have to repeat the steps bur wait one minute between each step so the computer and router have enough time to reset themselves.
If still no luck call on your provider for assistance.
Also note you may have switched off the WIFI program on the computer accidently, If you don't see a little icon an the task bar showing a signal strength icon that is active you will have to activate it.
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