Why won't my screen turn on?

For some reason, my Nexus 7 2nd generation isn't turning on after reading the instructions given from Google Help, which was to press the power button for 15 seconds, charge it to a computer, charging it for an hour, and etc. Honestly, NONE of those worked. I thought replacing the battery would help, but as it turns out it would cost more money than to buy a new one or whatever. Please help me bring my Nexus 7 tablet back to life. I haven't been using it in months and it's bugging me. Thanks.