Having problems with my computer I returned it to the manufacturer who found and fixed numerous viruses, and also installed Norton Anti-Virus 2004. Now, whenever I try to open a PDF attachment to an email the PDF does not open. I have uninstalled Acrobat Reader and reinstalled it without fixing the problem. The computer runs Windows XP.

When running Outlook Express 6 with Internet Explorer Service Pack 1 installed, the most probable reason why PDF files will not open is that the inbuilt antivirus protection in Outlook Express has been enabled. This will block a lot of email attachments. You can disable this feature by going to the ‘Tools’ menu > ‘Options’¦’ and click the ‘Security’ tab. Untick the box ‘Do not allow attachments to be saved or opened that could potentially be a virus’. Click OK. Restart Outlook Express.

Should the problem persist, it seems the file association for PDF files may have become corrupted. This should have been fixed by reinstalling Acrobat Reader, but apparently not. To fix this problem, save the PDF file to an easy to access location (e.g., Desktop). Then, find the icon for the file, right-click on the icon and select ‘Open With’¦’ > ‘Choose Program’¦’. Find Acrobat Reader in the list of programs and tick ‘Always use the selected program to open this kind of file’ then click OK.