It is indeed helpful in assigning shortcut keys in WORD. However this didn't help in my case. It appearsas as if <ctrl>B shortcut assigned by WORD is ignored or overuled by a program with higher priority, or something like this.
Let's try to find out whether the issue only affects Word:
Open up WordPad and type out some text. Select a portion of the text and hit Ctrl+B. If it works and makes the text bold, then you know the issue is only affects Word. Otherwise we can determine that it affects the entire system and go on from there.
Hmmm, interesting. Is there any software that you installed just before this started happening? Some programs can set a certain key combination to start that specific program. For example, if you right click on a shortcut to some program, if you go to properties you can click on the "shortcut" box and define some key combination to start that program by pressing the desired key combination.