Replacing a keyboard key

[The Lurker]

Anyone know how to repair or replace a broken keyboard key (left shift) for a laptop?  The top part is extemely loose, but when I press down, it still functions.

[RussianTeenModel]

First, see if it can still snap in to place.  If not you need to replace the under-tray part because the little plastic part may be broken.  I've done that before.  Its a pain.  be careful if you buy "english" keyboard parts on ebay-they mean the UK not USA.