Norton new installation deleted all outlook express inbox and thumb USB

I installed Norton anti-virus on XP machine. Bringing up outlook express I noticed the "delete" button was gray, not black. I went out of outlook and then back in - all inbox emails were gone, including airline coupon. . I installed it on a Windows 7 machine. Put a thumb USB handout from a law seminar in and a horizontal green bar popped up and after 2 or 4 passes, it deleted the entire data. I couldn't stop it. Lost a lot of valuable data.  What happened? Purchased new at Wal-Mart.

JTB