My phone did the exact same thing today.. My screen went black for about 15 minutes before coming back on again.. and then when I would try to turn it on the screen wouldn't come up.. But my keyboard also stopped working.. Cricket said they couldn't help me even though I had insurance, Wtf! Anyways, I just did the factory reset on my phone & its working fine now.. So advice, Next time just do the factory reset and it should fix the problem.
I have same f.up phone. Never dropped it or got it near water. was working fine, then next time i pressed menu it was black. same deal everything works . Did the remove batt thingy, the up volume+send+power key thingy. nothing. now it doesn't want to stay on either. going to contact Huawei directly after this and see how far that gets me. Oh and I bought this phone from a friend so warranty is null. Happy fracking new year