First, see if there is an IME switch problem only in Word documents. Here's a good partner for Win7, as an example of the Word document in Office2010, to see how this IME switch resolves:
In the Options window, click Advanced, and then from the Right Detail window, locate the IME control is active and tick it.
Restart Word to see if the problem is resolved.
Of course, if not only the input method in Word is invalid, but also in other applications (such as Notepad) can not switch. Or some software from the shortcut keys and the system's default input method to switch shortcut keys conflict, we can change the system's default settings. Specifically as follows:
Right-click the Language bar and choose settings.
After the text service and input language window pops up, switch to the Advanced Keys Settings tab. Select an action (such as a language switch or full half switch), and then click the Change Key Order button to enter the custom window.
Define a set of shortcut keys according to your own habits, and save the settings.