Attachments garbled in Mail

I have a friend who recently purchased a 13" Mac Book. The Store/Geniuses got it all setup for her. She also has an existing iMac at home. The issue she has now is that on the Mac Book, when she gets emails that have attachments, they come across garbled. Opening the exact emails on her iMac, things work just fine. She's using Mail on the Mac Book and Thunderbird on the iMac...

Searched here as well as Googled, but only came up with the two main culprits for garbled mail -> corrupted font cache or the existense of Helvetica Fractions or Times New Roman Phonetic. Those problems are fixes for garbled emails (subject line, mail body, etc.), not attachment specific.

I'll probably take possession of the Mac Book soon to see/test for myself, but any help in advance would be much appreciated. Will try the Font Cache Fixers as well as install TBird to see if they help.

Message was edited by: Doanster1