First, you are out of luck with the MS Office discs, Dell will only replace missing applications software in the first 30 days.   A google search does not turn up anything on just restoring that one file, you must have the Office install discs.  The alternatives are to purchase MS Office (the 2007 version is the current version) or if you are not using Outlook 2003 (e-mail program) you can download the free (but they take donations) Open Office suite of programs that are compatible and comparable with MS Office and use them.  www.openoffice.org
When I start any MS Office 2003 product, it asks me for the disc with BASIC11N.MSI.  Dell never provided this disc when they shipped the system.  Now I need it.  How do I get the disc or correct this problem?  My system is out of warranty, so Dell won't talk to me. In MS Word, I tried to running Help > Restore, but it keeps asking me to insert the "MS Office Basic Edition 2003" disk. Background I have a Dimension E310 that had a boot  drive crash.  The drive was RAID1 mirrored and I was able to boot off the mirror.  When replacing the drive I chose to upgrade to a larger capacity. I installed the new drive and, with Western DIgital software, I copied the old drive to the new one and created a boot drive.  Then, after verifying that I could boot off the new drive and use the system, I removed the old working drive and installed another larger drive to mirror the replacement.  I have have two larger discs that are mirrored RAID1 and everything is working, except MS Office 2003. Dell, in their infinite wisdom, did not provided MS Office 2003 discs.  Now that the system has crashed, I need one and I can't get it from Dell.  Any suggestions as to how to get around this problem.
Can find BASIC11N.MSI after disc crash