I am unable to print PDFs on my workstation unless I drag them from a Windows Explorer session and drop them on an open printer window (Start, Printers and Faxes, double-click on printer to open window). I have Acrobat 9 Professional (ver. 9.4.2) running under Windows XP Pro (SP3). I cannot print a PDF from within Acrobat or from within a browser window. I have done a "repair install" on Acrobat and rebooted. When I try to print from within Acrobat or a browser window, I do not receive any form of error message. There is no indication of any problem. If I have the printer window open window (Start, Printers and Faxes, double-click on printer to open window) and I try to print from Acrobat or a browser, I never see anything appear in the window, even briefly. If I drag a PDF from Windows Explorer and drop it in the printer window, the document name appears briefly in the window and the document prints.