Please show how to find the IRR/NPV using Excel.

So let's look at an IRR/NPV question that deals with refinancing. A couple decides to buy a $300,000 property by putting 10% down and borrowing the rest using a 30 year fixed rate loan with an annual rate of 5%. Determine the monthly payment. After one month the value of the property goes to $310,000 and stays that until the end of the loan. After five years, the couple decides to refinance the mortgage using a 20 year fixed rate loan with an annual rate of 4%. The refinancing costs are $4000 and the couple includes the costs in the amount borrowed on the new loan. Determine the monthly payment. The couple holds the property until the new loan is paid off (20 years from the time of the refinancing). What is the IRR/NPV from refinancing? Use a discount rate of 2% a year for the NPV calculation. (The discount rate is also known as the cost of capital mentioned in the "refinance discussion" post. It can be difficult to calculate, that is why I would give it to you on an exam question.)