I tried powering up my tablet but it doesn't power up after many tries with many cords and Sears won't take it back. What is wrong?

I would try using another charger and plug and power cord to see if it will charge again and another power outlet too. If it is still not charging then the battery needs to be replaced.

Hello

Reset the Device:
If your Kindle Fire won't move, this doesn't necessarily mean that it's "broken" or has a major problem. The Kindle Fire has a tendency to become "stuck," meaning that it looks like it's "off" when it's actually "on" but it will not work properly because it's locked up. To unlock the Kindle Fire, do a reset by holding down the power button for 20 seconds or more. Then turn the device back on by hitting the power button again. If this doesn't work the first time, try holding the button down for 30 seconds or more. Most of the time, this will be all you have to do to get the Kindle Fire up and working again.

Charge It:
If resetting doesn't work, it's possible that your battery is dead. Try plugging the Kindle Fire into the charger and wait about 15 minutes before trying to turn it on again. If the device refuses to start up, try resetting it again.
If it still won't move, it's possible that you have a dead charging cable. Alas, the cables that come with the Kindle Fire are not known for their longevity. Try charging the tablet with another cord that has a Micro USB connection and see if the device responds. There's no guarantee that the charging cord from your smartphone will work with the Kindle Fire, but it's worth a try. If you get a bit of a charge, then you'll know that your Kindle Fire needs a new charging cable.

Try a Different Power Source:
if the charging cable appears to be working but the tablet still won't move, try plugging it into a different power outlet or the USB port on your computer.
If all of these troubleshooting tips fail, your Kindle Fire may have a hardware problem that requires professional help.

Visit here: Kindle Fire Support

Help My tablet won turn on what do do

Why Does My Android Phone or Tablet Not Turn On

all tablets can charge while you are using them, on rare occasion the battery will completely discharge and will need to be charged to the minimum before operating the tablet.

take the battery out and unplug it. Wait a minute and put it back, then try

try to hold your power button and home buttom at same time or 1 min it will rebooth it

You could go to the place you bought it or another tech store and see if they have another tablet like yours lying around so you could test out and see if it is just your power cord that needs to be replaced. Because most likely it's time to buy a new power cord. Hopefully you didn't fry the tablet's motherboard also that's why you should test out the power cord first.

Either the power cord, battery, or motherboard is dead.

Bring it to where you bought it and test it with a new power cord. If that doesn't fix the problem then have them fix it.

Pull the SD card from the top and make sure you have the appropriate update from the cruz website on it. Follow flash instructions.
Test the power cord with a voltmeter to see if its giving power. ****** works well too. Not really don't do that, I mean it'll work but get a tool to check it. Someone who works on cars or their house will probably have one.
If that doesn't work, open the back, pull the battery plug and then plug it back in. If it still doesn't turn on you're probably beat. You can look further into digging in and removing other internal parts to attempt to reset whatever it is that is wrong but most likely it's an issue along the power line on the way in or the jack itself. If it had a surge it'll be something further that is fried. In most cases you're buying a new one.
Keep an eye out for the t301 its much more capable and prices drop to about $70 during sales. The touch screen is real (capacative) which is a major improvement and you have a lot more space to download stuff.
goodluck