I am trying to get Zotero set up on my desktop and laptop. On my laptop, everything is running just fine. However, on my desktop, Zotero is opening up PDFs in Adobe. When I check preferences for Zotero it doesn't even include the option to use the Zotero PDF reader. I've attempted updated Zotero on my desktop, and just followed Zotero's suggestion for file handling issues (deleting the mimeTypes.rdf from your profile directory). What else can I attempt?