Nokia 2 Megapixel phone

I have been having some minor problems with my phone for a couple of months now, where it would stall and anytime I press a button it wouldn't do anything. Now, this morning I was on the net on my phone and right afterwards, it froze up, and now,when I try to turn it off, and back on, it won't work. The screen is black and I can hear the tones when I press the buttons but, nothing is happening and I can't receive any calls. Please let me know if you can help. Thanks