The easiest way for you may be to uninstall the printer, then re-install it. I'm assuming it walked you through the wireless setup and that would be far easier than me giving you a step-by-step on how to do it manually.
Thanks. Before I could do anything it came on by itself as it had done a month before. I wonder if it connected to the fact that all of the telephones in my house that has VOIP, stopped working with the exception of one that has since stopped working.