In Windows XP Professional using an HP 5150 DeskJet printer that works fine printing from other applications, I am now unable to print PDF files displayed by Reader 9.4.2. In all cases, I get an "unable to print file" dialog box. If I close that, a new dialog box tells me that no pages have been specified even though I have taken care to specify the pages I want to print. I tried the procedure (found on or linked from this Web site) for printing files as images but I get the same dialog boxes and no printouts. I think it's possible that one of the Reader program files may be missing, but which one--and where can I find a replacement?