If these files are being received as PDFs, that's because they were sent that way. Neither Windows nor Office has a mechanism for converting email attachments to a different file format while they are still attached to the emails. As for the inability to open such attachments without first saving them, that might be a function of your email app's security settings. Windows Live Mail, for example, has a setting that prevents the opening of attachments that could contain viruses.

On the whole, your reference to 'I recently had the computer cleaned for viruses' suggests whoever did this cleaning took it upon themselves to change some of your email settings.

__________________
Cheers,
Paul Edstein
[Fmr MS MVP - Word]