CCFL backlights dim over time. If your screen has a pink or yellow tint, or flickers when cold, the inverter or backlight is failing. Replacement screens (LTN133W1, B133EW01) are cheap on eBay.
14.1-inch WXGA LCD screen with CCFL backlight and a resolution of 1280 x 800. sony vaio pcg-3c2l specs