An anonymous reader writes "At my large software company in the Northwest United States we've been asked to find ways to cut our budgets given the current economic client. We started by eliminating travel and reducing our workforce. Now management wants radical ideas to cut more. We use Windows almost exclusively here, and I keep reading on Slashdot how switching to Linux can save companies like mine a bunch of money. I know I cannot suggest switching to Linux without doing my homework first. What data do I need to collect and present in order to argue Linux has a lower TCO? Currently we spend 4 billion dollars per year on Windows. What percentage decrease is reasonable to expect? Almost all of our development effort is in .NET and Visual Studio, and many of our workers are the world's foremost experts in the technologies. Does the Slashdot community have experience converting and re-training a large workforce to use another language and IDE? How can I estimate the cost of porting existing billions of lines of code to Java? Is it possible that my company won't save money by switching to Linux?"