What internal control procedure(s) would be most effective in preventing the following errors or fraudulent acts?

1. A company started using a new payroll program and recruited a payroll officer. When this staff member entered an employees name who was an existing staff member, this new system asked the payroll officer if she wanted a new employee record being created. The payroll officer then created a new record.
2. When a staff member was no longer working for the company, there was no procedure in place to remove the payroll details from the system. The payroll officer changed this employees payment method and bank details so the wage was paid to a friend of the payroll officer.