Enable field

[Mavis]

Hi All,

I have created a query to pull out all currency use in all the claims.
I created a form with a subform to display the currency which pull out from
the claims.
In the main form i will have Text box for each currency. Example:
SGD:
JPY:
RMB:
MYR:
EUR:

I will need the text field of the currency to be enable to allow user to
enter exchange rate when it match thecurrency which pull out from the claims
and the rest will be disable.

Anyone can help to advice how can i do that?