How to make the scroll wheel to affect always what's under the mouse pointer? [duplicate]

In Windows 7 & 8 at least, type "change how" into the start menu/screen. You should see (under Settings on Windows 8) "Change how your mouse works". Select this and look for the option to "Activate a window by hovering over it with the mouse".

Now the window under the mouse will activate automatically after a short delay and scrolling will work as anticipated.

I'm not sure if this is available in earlier versions of Windows. Try looking under accessibility options in the Control Panel.

For the sake of completeness, lets list all the options:

• Change the Ease of Access settings (as given above, works with at least Win7+, maybe others)
• Use TXmouse as suggested by @Sean-Cheshire in the comments (last updated in 2005)
• Change registry settings - see the question "Setting focus auto-raise and focus auto-raise delay in Windows 7"
• Use WizMouse which has the advantage that it doesn't affect the window order like the other answers do. However, it does have some compatibility issues (see the web site). Supports Windows versions from 2000 to 7, not sure if 8 is supported.

UPDATE: From the "Update 2" in the question, I'd say that WizMouse is your best option as long as you can live with the limitations listed which seem to revolve around touchpad and Logitech issues.

I use a wonderful little piece of freeware called Katmouse.