Windows Mail doesn't receive attachments!

Hi Everyone, hope you can help this newby!

My problems is that I am unable to receive mail attachments properly (.doc, .jpg, .pdf) with Windows Mail on Vista Home Premium. The attachments are corrupted - eg only part of a picture and the .doc/.pdf files cannot be opened ("insufficient data" and similar error messages).

Under Tools, Options, Security "Do not allow attachments ..." and "Block images ..." are both unchecked. The Avast! AV Internet Mail scanner is terminated.

The messages and attachments are received fine on my other computers running XP (Outlook Express), Avast! AV and ZoneAlarm.

Other than changing to a different mail program (I've been advised to try Live or Thunderbird) can anyone offer some suggestions to fix this problem?

Many thanks!

Update - same problem with Windows Live Mail, too!

Although the .jpg attachments are received, the reported file sizes are not the same as on the outgoing message from Outlook Express (under XP), only the top part of some of the images shows in the email, and the attachments cannot be opened. If I save the attachments and then open them, the appearance of the image is the same as previewed in the email, i.e. most of each image is missing.

Greetings All -

Can no-one help me with this?
Gary?
Any suggestions gratefully received!
Thanks