just games or most windows software...say like professional software like cad and solid works.
Direct support lacks to most windows software. Many can be run directly with Wine though. But there are open source alternatives to most commonly used programs. Photoediting, video, instant messaging, audio, even games... Only teenagers who need to run crysis will be blocked out basically.
Also some professional use programs may not run but for general type of office work (handling office, excel etc.) Linux works better straight out of the box than windows, it has libreoffice built in. Some may cringe on the differences of use, some welcome them as its NOT using ribbon but the 'good old' style of UI.