Computer just decided to turn off completely last night and won't come back on, I left it charging…

Computer just decided to turn off completely last night and won't come back on, I left it charging overnight and still won't. I'm about to freak the fuck out, I don't need this! All of my work is online and I can't even see what I have to do without a computer! I should've just bought a brand new one instead of trusting that the computer my stepmom let me use was gonna work for me. Where could I take it to get it looked at? What kind of store? I already got zeros for shit that I had due at midnight bc it died in the middle of me trying to complete it. And I have things due tomorrow and the 30th that I NEED to get done!