My konica minolta c450 touch screen not working at all

SOURCE: Konica Minolta C450 User Manual

http://kmbs.konicaminolta.us/content/products/models/bizhubC450.html?info=Manuals

SOURCE: proplem with KONICA MINOLTA bizhub C450

c-3451

SOURCE: KONICA Minolta c450 in Windows Vista

go to the printers and faxes page and in the driver properties click on printing preferences click on authentcation/account track and you should be able to enter you name and password from there unless you may have to be logged on as the administrator on your computer to make these changes

SOURCE: Konica Minolta Bizhub C450 touchscreen doesn't work

You need a new touch screen panel or I/O cable, they are fairly expensive if you don't have a service contract with your Office Printer supplier. Recently just replaced one a few months ago.