A router will automatically find what it considers to be the best wireless frequency to connect to a PC. You may find that in your house a different frequency would be better so it allows you to change to a different one.
Incidentally if you've left the router switched on all day today you've probably left it to late to fix your security.
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Do you know that we're all in line for succession to the throne? Really?
Well, if forty-eight million, two hundred thousand, seven hundred and one people died I'd be Queen.