Why still use Windows, not free Linux?

Why You use Windows as an operating system when Linux is free and offers almost the same kind of software?
One just need to burn the CD or install from USB flashdisk

Example linux distributions:
http://distrowatch.com/dwres.php?resource=major
http://www.howtogeek.com/191207/10-of-the-most-popular-linux-distributions-compared/

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in my case im still with Windows because of:
- two computer games (im not sure if Test Drive Unlimited would go on Linux anyhow)
- Miranda IM (instant messenger for Skype, GoogleTalk, YM, MSN, ICQ - all in one) ... maybe Pidgin would work for this, but i did not had time to test it fully