how to set a time after unsuccessul attempts?have a sample for that?

After unsuccessul attempts for ore than 3 times, the password unload (mean the user cannot enter that module.. It ok.. Then When I try again... the message box Please put correct password always appear every time I enter invalid password despite I have enter the invalid password more than 3 times. It suppose unload after 3 times unsuccessul attempts.. The the first action it ok..But when I try back...the messagebox always appear and I need try it over and over untill I enter the valid password.