Slow Speed due to router

Hi there,
I had a problem, my internet was working slow on wireless and when connected with wire it use to fly like anything.
What i found from reading alot if that often people think that there router is conduction some problem after few years of usage and the signals are not omitting correctly or something.
However I got a simple solution for you all I found that the internet was absolutely fine when connected with wire.
So after doing alot of other activities i found that the FIREWALL was turned on, on both the devices i.e. My ROUTER and my DSL MODEM.
So please keep in mind usually there is not problem with the Router or the DSL modem if you feel the internet is slow please check your firewall and simply turn one firewall on either it should be routers or dsl modem.
Well this helped me and now i get good speed.
If there is anything i can help you with please do not hesitate to ask.
Thank you :)