The greatest problem with M$ is that they are a monopoly, and they got there through highly unethical business practices. The embrace, expand, extinguish policy, the attempts to destroy competition through lawsuits, business deals ... SCO, Novell, etc. They have been fined millions of dollars/euros per day in Europe in an attempt to make them comply to the requests of the EU to be ethical and not extinguish all competition. Let's not even talk about the quality of their product, even if they didn't plan to make Window$ such a POS, it has made a huge market for software, and especially for malware. On many occasions they have known of a certain exploit for many years but not told anyone until they knew they had to ... the $ony rootkit thing. There also exist files in Window$ that are hidden from you, so hidden that very few people know about them and how to find them. Probably there are many backdoors in it too. I also probably should not mention Vi$ta, the zenith of DRM, or rather "DRM masquerading as an operating system". I could go on and on, but there's plenty on the internet about all this, you just need to look. The final conclusion is, this company must be buried deep, so deep that the disease it carries will be contained forever.
From the way things are going M$ will start loosing big time in a couple years time, then maybe in 10-15 years it will have been destroyed by itself. It's inevitable, it will happen. So far it is forcing people to upgrade to Vi$ta, as many news articles say people aren't upgrading. Window$ 7 will then be release and they will try to force an upgrade again, people will not upgrade. The other OSs by that time will gain support because they have superior features which XP cannot handle no matter how much they patch it. It will get caught in its own trap and die in it. I can feel it :)