Regarding missing attachments, are you talking about vistas Windows Mail program, or the Outlook email website that replaced hotmail? I think the Windows Mail program may be quite buggy, judging by some online forums. Google brings up a lot of results.
Can you download your attachments via the outlook website? If the attachment symbols are not present, try logging in with another browser such as firefox. If that doesnt work, its either a microsoft or sender issue.
I switched from hotmail to yahoo mail and use thunderbird to access all of my email accounts from the desktop. You could try thunderbird to see if it fares any better with your microsoft email attachments. It supports them, click here