Hiya guys~ I have had a PSVita for quite a while and it has been fine. I haven't used it for a while though and it has been sat in my bag for a while but today I went to turn it on and not even a light came on, so I guess it needed charging, so I put it on charge, but even the orange light didn't come on. I don't know what could have happened to break it but it does seem broken :S
I'll assume you've already tried this. How long did you attempt to charge it? I've never let my Vita battery drain all the way down to 0%. Usually get close though because I read it's a waste if you charge as soon as it hits 50%. But I've used MP3 players until they hit 0% battery life and they didn't show any signs of life until a few minutes of charging. Maybe try charging the Vita for 5 minutes and see if the light comes on? Can you plug the USB cable (I think that's one of the two cables you usually use to charge the Vita) into a USB slot on a PC and charge that way? If that works, then the Vita adapter is the root of the problem and you only need to buy a new adapter. If it doesn't work, then I don't know what the problem is ^^; (Although that link suggests it could be the battery)
Try twisting and moving different parts of the cable, to rule out it's not the charger. Be very careful that it's isolated, and not damaged, otherwise don't touch it. Don't know which kind of batteries the PS vita has, but it seems to be the main suspect. Some batteries will refuse to be brought to life if you let them lying around for a long time. For some reason (greed *cough* and incompetence *cough*) this seems to be the trend right now. Sometimes to store them on the fridge works, but if it doesn't just buy a new one and let your local geek take care of the op. Workshops are an option too, but they are business, not charities, so expect high prices for little jobs like this one. Oh, and I don't want to scare you, but there is no leak, right? If there is leakage and it went to the mainboard, the repair can get pricey, depending on the damage.