Assuming that the QWERTY keyboard is sliding fully home then it sounds like either the latch, or whatever it latches to, is broken.
Take a closer look and then see if you can repair!
Broken (weakened) spring? Piece of plastic snapped off?
Is the keyboard itself working OK? If not, then you should be able to substitute it without too many problems. There should (may) be a USB connection inside (the keyboard).