exchange server mailboxes PLEASE HELP!!!!!!

HELP somehow a mailbox on my exchange server has dissapeared. only one users mailbox, we are using outlook as the exchange server client, but anyway, his mailbox on exchange server is GONE, and he had over 300 contacts stored in it,that are VERY important. we backup the server everynight, with seagate backup exec. however we do not have the agent to back up exchange server. but backup exec does back up the whole server. is there anyway to go into the backup tapes from previous days and restore this one mailbox?? or even to restore all the mailboxes? any help on this matter will be highly appreciated.

Beth,
Sorry about not answering about the tape backups, but make sure the mail account is truly deleted:
1. In Admin.exe program, from pulldown menu "VIEW" click on menu-item "Hidden". That is to make sure that the mailbox was not accidentally hidden (equivalent to "disabling" the account).
2. In Admin.exe program, modify your column views to include "Date Modified" when viewing all the mailboxes. Sort on the date modified column (by clicking on it). See if someone perhaps changed the display name of your "deleted" user. Also, make sure that his NT id was not deleted or the associated NT account with his mailbox was not removed.
3. If you are really lucky, he may have an off-line "OST" file on his C: drive.
Check his C drive for the following "*.PAB", *.OST, *.PST files or some archives of email there.

Thats off the top of my head, otherwise unless you are doing a "brick" backup, I believe all the mailboxes (the Priv.edb) will need to be restored on a separate server. Microsoft has KnowledgeBase articles on this ("Disaster Recovery Part I and Part II). Find the sections that apply to recovering one mailbox and read it since its a complicated procedure.
Another source is : www.msexchangestuff.org" (or www.exchangestuff.org)
Good luck.

Backup Exec by veritas is a very good program. However without the Exchange modual it will not backup open files. Unless you are stopping exchange services during your backup it will not backup your open files.