Oil Pan Gasket

A friend of mine who has a S60 is going through oil rather quickly. He thinks that it's because of a leak oil pan gasket. Is replacing this is very complicated? Also, he has a problem with the driver's side window. I know this is somewhat of a common problem with various makes. Is this a pattern failure and if so what might be the cause. If any of these problems are simple enough, we might take attempt these repairs.