I'm a noob when it comes to the computer world so bear with me. My laptop is about 3 years old and about a year ago, my sound started to get muffled and I couldn't hear voices when I played games. Whenever I move the earphones in the audio jack, I can sometimes pick up the voices, but I have to keep it steady of put a pillow under it to keep it like that. Is it just my computer? Or did something change?
Either the headphone jack is defective or the headphone plug. To determine which it is, use a different headphone (or the small earphones like are used on MP3 players) and see if that works properly. If it does then the jack in the PC is the problem. Unfortunately either the motherboard or a "daughter board" I/O board will have to be replaced. The jacks are enclosed and not (usually) repairable. The printed circuit boards are multi-layer and unless you have the special tools to work on a multi-layer circuit board you can't fix it yourself by replacing the jack.
One other outside possibility. A few PC's, but not all, have the option to reassign the jacks with a Sound Configuration panel. If yours has this, you MAY be able to make the "Line In" jack a headphone jack.
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