When I try to turn on my camera (Samsung Digimax S500), it beeps 3 times.

Well, have you ever considered that the lenses MIGHT be defected? If it's true, you can send it back to the manufacturer, as long as it wasn't YOU who made it defected.
Another tip, is maybe the lens isn't made for that type of camera.
Lastly, the lens can just be broken, so you should carefully examine it, and see INSIDE of it, to make sure all of the parts are their. Hope this helps (:

I have a samsung digital camera digimax cyber 530 - just replaced batteries and camera wont start, i get 3 flashes from the green light screen nw comes on then goes off & the lens wont retrack back in the camera

BAtteries draws down too quick...
Use 2500 mAh or better for longer life the higher the number...
eveready bunny is sometimes not in all their work

Everytime I try to turn it on, the lens comes out for about a second, the camera beeps 3 times, the lens retracts and the camera shuts off. The battery is completely charged and the camera is only 4 months old. HELPP :(

There appears to be no rhyme or reason to your query - I advise you to contact Samsung directly,

dont buy this c*#p again thats the best solution i can give

sounds like a lens error, does the lens extend or retract? You probably have to get the lens back on track, use gentle pressure wiht the camera face down on a towel covered table and turn on to see if the camera tries to retract the lens. I really dislike these types of cameras that extend the lens everytime, if it turns on in your pocket, your doomed!

Same thing here

Mine got stuck with lens out. The batteries were new so I never imagined it could be the batteries, but they were cheap ones so I recharged a pair of good ones and once I put tried them on it worked just fine again. Conclusion, the "new" cheap batteries had only enough energy to turn it on and then they couldn't give it enough energy to make it work anymore and that's why I couldn't retract the lens or even turn it off properly. So in your case, try using a couple of good and new batteries.

Use lithium batteries. I had a problem when our camera would turn on for a few seconds, beep 3 times, and then shut off. The best batteries, which are actually recomended for this camera is the lithium batteries. I strongly suggest them.