Data missing in Form

[Nancy at MPHI]

Here is what i have: I am using Access 2003. I have created a DB, stored on a
network, which is designed for data entry using a Form. There is only one
form, and the record source is one table. In the source table, some fields
use lookup values from other tables, and these show in combo boxes on the
form. There are also text boxes in the form. The form is set up to not allow
new records. The table has all the records for which entry of (new info) data
is expected. The data entry person searches for a record ID, and then enters
the new info into the form. Form properties: allow additions, allow deletions
and data entry are set to No. Allow edits is set to Yes. Most of the fields
are in a Tab control with 5 tab-pages.

Here is the problem: On several occasions, as the data entry person is
actually entering data into the form, all the fields that she has just filled
in show blank instead of what she just entered. Data is disappearing in front
of our eyes! No pattern on when this happens. When I pull up a backup copy of
the DB from the day before and enter in the same info into the same
(blanking) record, it is fine. Can’t replicate the problem. I checked that
the form and table have the same data (no widow/orphans).

Any ideas? Thanks much in advance!!