I'm not too sure how to explain what's wrong, but I will do my best. The first thing I did was put it in the charger, it was around 50%. The time was 12:03. I did something, I cant remember, I tapped the screen or something, but it froze and multi-colored (mostly white) lines started to appear on the screen till everything was covered up in the lines and it turned off. I took it off the charger and left it. This morning I tried to turn it on, but it didn't work, so I plugged it in and tried again, it turned on, but the turning on process was way quicker than usual. When it was fully on, the time read 12:03 (the time was actually 9:27) and it showed the battery as being 100% (even though I didn't leave it to charge). Now it wont turn on unless it's plugged in.
Additional information: The guarantee says it should have at least another month. It's second hand so I probably shouldn't trust the guarantee. I've dropped it heaps.
Thank you for reading this, I know it's a lot, but there's a lot to say.