Think from an auditing perspective, how would you keep segregation of duties and perform auditing procedures even though all of it can be done by one user? How does the contravene with the Sarbanes Oxley Act?

If you don't know what segregation of duties are, they are a set of rules within the accounting process to provide checks and balances during the processing stage. Example: If QuickBooks allows you to write checks, create vendors and customers, process payroll what is to say that one could not influence or manipulate records for personal gain?