I bought a D3000 about a year and half ago and now it's starting to develop hot spots and dead pixels D:
I don't think that's a problem, unless you mean blooming and a dirty sensor, which I doubt you meant.
You probably just meant "hot pixels". This is completely normal. As in exceptionaly normal. I have not encountered a DSLR that did not display hot pixels. Nor do I know of any fellow photographer who has not discovered them either. It's part of the technology, it's not a problem, "it's a feature". lol
They are just overcharged or leaking photodiodes.
Oh jeez...hope that doesn't happen to mine!
Chill
Well I never noticed it until I took a picture of something black (my monitor had a black background) and saw a red dot. So then I tested it with the cap on, at high iso and long exposure and then I found 3 dead/stuck pixels ( one red, one green, one blue) and several little white hot spots. I was lucky because I had about 2-3 days before my warranty expired. So I sent it in and got it back in about a week but one red pixel was still present. I would suggest you check your camera for dead/stuck pixels and hot spots every month before your warranty runs out.
Those conditions happen to make hot pixels more apparent. The more strain on the photodiode and the hotter it gets you are likely to achieve the ever glorious hot pixel. WoooHooo! =P
Learn to spot them quick and edit them in your workflow and you will be all the better off for it. By the way, you don't need to push your camera to the limits for them to appear. Some cameras are a little more prone to them than others (especially older ones) but they move around a lot and they often come and go.
Unless you have a really dirty sensor and are scared to clean it don't send your camera in for hot pixels. You are not doing yourself a favor, and they are not doing anything for you. I promise you. And I can assure you they will never replace your sensor for said issue or even look at it twice.
Life is good, all is well, go take some photos. =)