What makes Windows so popular?

bercause it has been out the longest and now its so big.

Its GUI(Graphical User Interface) and easier of use for beginners

I think because windows is more easy to use. I'm not say linux is not good everyone have bad and good side depend on how we will use that technology will be help a lot for us..

B'cos Microsoft marketing team is marketing it. While who is marketing the Linux. Its those who are using it. While most of the corporates WANT to pay and pass the responsibility to M$ its like this if your Computer Administrator says to you that something is not possible in his IT network/computer you (& the TOP Management) would believe it. While what the Computer administrator might be telling is that it is not possible in Windows. Also there is an attitude in the Computer departments of Non-IT companies that "why take headake of deploying and maintaining Linux when all your day to day tasks can be easily done with windows. Now figure this: All your day to day task can be handled with PI generation of CPUs while windows do not support it hence vertuly everyone have migrated to P4 and what not. Major reason is WindowXP (currently supported by M$) do not work on PI while you can still use the Linux on the PI and get same work done on PI.

i dont think it is very popular.

I think because MS was selling it to users. Unix was destined for o made professinals, programers and enterprises. When Linux appeared on the scene it was not as well marketed as Windows. It was not commercial and no one ever wanted to sell it. Windows is a commercial PRODUCT, not the best one but well advertized, promoted and sold, while Linux was attractive for smaller group of people who just wanted to get rid off their Windows and try something else. If there were a person who made Linux a commercial product with marketing and advertizing it might overcome Windows, but... it never happened and will never happen unless ALL Linux users promote it for themselves.