Not your run of the mill PC forum question, but here'goes:
Today I swaped out my original Dell keyboard with a Sidewinder X4 keyboard. Being a gamer, the feel of a keyboard is important. Being an FPS gamer, its VERY important (BC2, BF3). My only gripe is that the lower row of keys are less pronounced, that is they are more flush with the top of the keyboard making it harder to find these keys by feel. The Dell keyboard was great because I could hold L-CTRL with the outside of my left palm while keeping my pinky on shift.
Now rather than retrain my finger movement or remap the key in-game, I want to build up the L-CTRL key somehow; layers of tape, a gummy substance that will harden and not flake or smude, etc. The heat from my hand and from the keyboard will complicate this.... I want my Dell L-CTRL back
Try using Super Glue with a Straw (Hard Plastic one) filling it up with a little silicon and a Ball Point Pen Spring.
It will help increase the height of the left control and be sturdy and fine.
Or just try to remove the L-CTRL key from the Dell Keyboard and see if it fits onto your Sidewinder, if they are compatible then all you need to do is just exchange them.