It just stopped working! Is there a reset button or something?

Have you tried an AC adapter? If you can get the camera to power on with an AC adapter, that'll point to the batteries as the culprit.

Often, when you purchase batteries in bulk, it isn't uncommon that some or many of them are near dead or worse. Batteries bought in bulk tend to have a long turnover and such, can lose much of their battery power before they are used. And many batteries such as AAs are general purpose batteries and are not designed for the high energy use of digital cameras and the flashes they trigger. As such, I recommend using high energy batteries designed for digital photography. Varta is a good brand. They are usually sold in camera shops, are long lasting (because they are sold in small quantities) put out alot of energy.

And, even though you think you've put in fresh batteries, underpowered batteries are just as bad. At the very least, make sure you are using Alkalines. Even better, batteries with a higher mAh - like around 2500mAh would satisfy the higher power requirements of your camera.

Resets can be done either by replacing the batteries or accessing the reset feature through the settings menu. If you can get it reset, you should be fine. I'd also go to the website and download the latest firmware update.

But since you say that your camera isn't working, you may need send it in for servicing. Be advised, however, that if it's out of warranty, it may cost more to repair than it is really worth. The rule of thumb is that if the estimate for repair is north of 50% what you paid for it, you're better off taking that money and buying a newer and upgraded model.