Misfeeds and partial printing with CX8400 on Vista Machine

I have a brand new CX8400 connected to a brand new HP 8200n Media Center PC with Vista Home Premium (32bit). From day one my printer will regularly print only part of one page, then begin feeding blank pages through until cancelled - or feeding pages through and printing one line of ascii text at the top of each page until cancelled. I went through all of Epson's online help, got a replacement printer from Epson that proceeded to do the same thing, then spent several hours on the phone with Epson techs helping me remove and reinstall software and drivers. Finally Epson gave up and basically told me I should contact HP. HP has not responded to my online help request. Any ideas or solutions would be most welcomed.