Why does my data disappear when using Microsoft SQL Server Compact 3.5?

I am creating a distributed application in C# using a database. The connection data source is: Microsoft SQL Server Compact 3.5 (.NET Framework Data Provider for Microsoft SQL Server Compact 3.5)

Here's what happens:

If I run this application locally, in design mode, it stores the data. The data will remain in the table until I try to view the contents of the table by using the below menu:

When I do that, the table shows no records. After I do that and re-run my app, the data is all gone. If I don't try to view it, the data remains no matter how many times I stop and start the app.

Weird?

Anyway, once I build and publish my app, using the Build menu, the app will not retain any information I enter at all.

Any ideas why this might happen?

Below is a piece of code that writes info to one of the tables, just in case it's pertinent.

    private void fF_tblParamsBindingNavigatorSaveItem_Click(object sender, EventArgs e)
    {

        SqlCeConnection con = new SqlCeConnection();
        con.ConnectionString = FileFinder.Properties.Settings.Default.Database1ConnectionString;
        con.Open();


        //Create the SQL string and then add the variables
        SqlCeCommand com = new SqlCeCommand("update [FF_tblParams] set FileSize=@FLen, DateLastAccessedLT=@FAccessLT, DateLastAccessedGT=@FAccessGT, DateLastModifiedLT=@FWriteLT, DateLastModifiedGT=@FWriteGT", con);
        //SqlCeCommand com = new SqlCeCommand("INSERT INTO FF_tblParams (FileSize, DateLastAccessedLT, DateLastAccessedGT, DateLastModifiedLT, DateLastModifiedGT) VALUES (@FLen, @FAccessLT, @FAccessGT, @FWriteLT, @FWriteGT)", con);

        com.Parameters.AddWithValue("@FLen", fileSizeTextBox.Text);
        com.Parameters.AddWithValue("@FAccessLT", dateLastAccessedLTDateTimePicker.Text);
        com.Parameters.AddWithValue("@FAccessGT", dateLastAccessedGTDateTimePicker.Text);
        com.Parameters.AddWithValue("@FWriteLT", dateLastModifiedLTDateTimePicker.Text);
        com.Parameters.AddWithValue("@FWriteGT", dateLastModifiedGTDateTimePicker.Text);


        com.ExecuteNonQuery();

        com.Dispose();
        con.Close();

    }

This is my first ever app using WinForms, so please pardon what might be a n00b question.