This paper introduces a new method, different from the discounted cash flow (DCF) method, for the first time, to estimate NPV and IRR. This method makes use of the capital amortization schedule (CAS). The functional relationship between the closing balance in CAS and the NPV is derived and illustrated. Accordingly, the present value of the closing balance in a CAS is the NPV. NPV is estimated using the new method for some selected normal and non-normal net cash flow (NCF) investment projects and presented here. The estimated NPV perfectly matches with the NPV estimated by the DCF method. This method is more transparent and provides a better insight into the suitability of the NPV criterion. NPV represents the unutilised cash inflow and when it is fully utilised, the NPV will become zero and return on invested capital will be the highest, equivalent to IRR. Also, when the cost of capital is in percentage term, the return on invested capital (ROIC) must be in percentage term like the IRR and not in two parts viz. percentage term (hurdle rate) and the balance in absolute term (NPV). The method presented exposes the weakness of the NPV and raises question about its validity as a criterion in capital investment. The CAS based method also makes it implicitly clear that there is no reinvestment of the intermediate income. As the modified IRR (MIRR) is based on the assumption of reinvestment, MIRR might become redundant if there is no reinvestment. Text books and other published works related to Corporate Finance, Investment Analysis, Capital Budgeting and cost-benefit analysis must review these findings and consider revising the relevant chapters or sections accordingly.