multiple textbox validations

Hi,
I have a registration form with bunch of textboxes.
I have a single main Label  on the top of the page that shows message if validation failed.
I wrote all validations in one function contains if..else statements for each textbox, if textbox failed to validate - the label shows a message, else - the label content cleared out and painted with white color (to hide it)...
so the problem is if one of my textboxes failed on validation, the label writes it, and if the next textbox validation is OK, the Label turning to white and hides the message of the non validated textbox.
how would you recommend to write the algorithm?
Regards