THE@ AND # SIGNS NOT ACCESSABLE VIA THE NORMAL KEYS

When typing on my Lenovo laptop I had ocassion to want to type the @ and the # symbols.I pressed the relevant keys for this .The symbols that were displayed when I did this were ” and | respectively.I have discovered that to get the @ and # sign I must now type the number 2 and number 3 respectively with the upper case button pressed at the same time.
Can anybody please assist as to why this has happenend or suggest how I can get them back t their correct position on the keyboard.
I have tried to reinstall the driver for my keyboard which is running windows 10.
Many thanks