There's really not enough detail in your post to help your specific problem, so I'll make up an example.
In your combo box, choose RowSourceType of Table/Query, let us say you have three fields in table1.
Make your RowSource "SELECT FIELD1, FIELD2, FIELD3 FROM TABLE1;"
In the Format menu, choose ColumnCount to be 3 and make the column widths 1";1";1".
Please note you can only bind one column in your combo box, so you may need to use DLookup or .Columns to obtain the unbound values, if you need them.
All code ADO/ADOX unless otherwise specified.