How do I get license for Quartus II v9.1 sp2? We already have the FPGA Stratix IV board. Please give a number or link. I don't have license activation code or anything.

Do you have the Altera account credentials for your university? If so, go to the webisite mentioned by Calvin , choose the Standard version as it supports Stratix IV. Once you get to the next page, you will be able to see a Renewals tab. Select that tab and check if the university's old expired license is shown. IF so, then select it and click the Apply Renewals button.

If this also doesn't help, then you need to contact Altera sales /University program and find out about licensing.