Unbound form to add data only

[Breno Aguiar via AccessMonster.com]

Any one that could save me on that:
I have a form (unbound) that have three text boxes. One is capturing the
username and real time (=Current user & Now() )"usertime", one is called
"addnotes" and another called "compcode". What I need is to combine the
information typed in the "addnotes" text box and in the "usertime" text box
and send that to my NOTES field in the UNITS Table. The UNITS table had the
primary key the "Computer Code" field. The user needs to type the COmputer
code in the UNBOUND text box "compcode" so it can add data to the right
record. But that needs to be adding data only and not deleting the previous
notes on that record.

Any help would be really appreciated!
Breno