I have a user asking about viewing PDF files in Internet Explorer. When she clicks the file link on a website, IE prompts her to save the file, which she then has to open to read. What she's not seeing in the prompt is the ability to open the file without having to save it, or, just opening the PDF automatically. She and a few others are having the same problem, while a majority of the user do not have this problem. All of the users have IE 8 and Adobe Reader 9 installed. I've verified that Adobe Reader's "Display PDF in browser" option is enabled.
What else should I check?