Sony laptop- shift lock

Hello,

I have been having issues with my sony vaio laptop.
while I am typing, I press a combintation of keys that prevents me from typing.
If I press enter or backspace, nothing happens.
If I click no a different area, the whole section gets selected.
I can not continue to type. If I exit the program and click on a desktop icon,
all of the desktop icons get selected.

In the end, I have to turn off the computer and restart.

How do I undo this problem when it happens to be again without having to restart the computer?