Have to restrict the user to view the employees.How to achieve this?

 Hi

 I want to make restrictions to the user to insert/update employee details.Need to provide view only access to the employee records.How to achieve this?.i.e Can able to hire the applicant.But when the applicant is hired as an employee,his/her details should be view only.

I tried using the custom security profile ,the form will show up only the applicat details.If the employee number is provided,it wont show up.In the search by window we will get an error stating invalid number.But now i need to view the employee details also,but it should be view only.