The Super User question [How to make ^ and ` non-dead-keys on Windows 7 with German keyboard layout](http://superuser.com/questions/280005/how-to-make-and-non-dead-keys-on-windows-7-with-german-keyboard-layout) is about the reverse situation. In an answer, [Tobias Plutat suggests](http://superuser.com/a/280032/151741) to use **The Microsoft Keyboard Layout Creator**, which allows you to

> assign or un-assign dead key behavior

The tool [can be downloaded from microsoft.com](https://msdn.microsoft.com/goglobal/bb964665.aspx). According to its installation requirements, Windows 7 is supported (it doesn’t list Windows 7 on the download page you get redirected to, but the documentation on that page seems to be for the older version 1.0, not the current 1.4).

As I’m not using Windows, I couldn’t try it, but at least on GNU/Linux the behaviour you desire is the default one if <kbd>^</kbd> is set as **dead-key** (except for <kbd>^</kbd>+<kbd>u</kbd>, which creates `û` instead of `ŭ`, which makes sense, I guess), so I assume it should be the same for Windows. At least the `â` is listed on Microsoft’s [Common Dead-Key Combinations](https://msdn.microsoft.com/en-us/library/cc195156.aspx).