I installed a new HP C5180 printer in June this year. All went well and initially, in the first few weeks, the buttons on the printer functioned and using them I could easily make a copy of a letter, etc. placed face down on the glass. It will no longer do this, the buttons just don't respond. I can only use the printer through my computer using which I can scan in and print, and print any file, (doc, pdf, jpg, xls, and so on), located on the hard drive without problem. Please, why do the buttons on my printer no longer work? My operating system is WindowsXP.