User gets multiple copies of emails

I have a user who is running Win98SE and Outlook 2000. We are using Windows 2000 Small Business Server. This problem is affecting only 1 person. She needs to have internet email for one of her applications which sends queries to a vendor. I have setup the SMTP server address as that of the exchange server. Everything had been going great for months…then it stopped working. I found that her connection had lost it’s setting. I set it back up and used her NT acct. and password to log on to the SMTP server and now she gets many duplicates of all her new emails. Any thoughts????