I have a 13" Macbook that, all of a sudden, cannot find my HP 4280 printer on my network. The Printer is plugged into my 21" iMac, and I'm using a Linksys router. I never had any trouble until recently, and when I open up the "Printers and Faxes" option in System Preferences, my printer isn't listed. When I click "add a printer", it's not there. I have cleared my printers and reset everything, but it hasn't fixed it. I can plug it in via USB and it recognizes it, but it won't find it via airport. Any recommendations?