It sounds like you have accidentally pressed a keyboard shortcut that affects its settings.
Go to Control panel, Region & language, Keyboards & languages, Change keyboards, General tab, select the correct keyboard or click on Add*... & select it from the list first. [* this can be very useful as it shows images of the keyboard layouts for you to select from]
Afterwards, go to Control panel, Region & language, Keyboards & languages, Change keyboards, Language bar tab and, if you don't routinely need to change language settings, make the language bar hidden.
Then, go to Control panel, Region & language, Keyboards & languages, Change keyboards, Advanced key settings tab where you will see the shortcut key sequence that probably got you into this problem by accident. You'll also see the Change key sequence that you might wish to alter by clicking on the Change key sequence button and setting Switch input language & Switch keyboard layout to Not assigned [when I changed these, I had to set Not assign for the Switch input language and accept the change then come back to the dialog to set Not assign for the Switch keyboard layout].