Gobii ereader wont restart after delting books seems to frosen

What does it say when you try to open them?

Per Amazon: If your book won't open, there may have been an error downloading the book.
To download the book again:

1. Connect to Wi-Fi.
2. From Home, tap My Library, and then tap the Downloaded tab.
3. Press and hold the title of the Kindle book, and then tap Delete This Book.
4. Tap the Menu icon, tap Settings, tap the Menu icon again, and then tap Restart.
5. After your Kindle restarts, tap the All tab, and then tap the title of the Kindle book to download it again.

Amazon has several suggestions other than the one I listed above. Here is a link to another suggestion:
https://www.amazon.com/gp/help/customer/display.html?nodeId=201460960

Strange as it seems you delete it online. Log in to amazon Hover mouse over account and lists. From the drop down list click on manage content and devices. Look for the book in the list and click the check box on the left. Click delete and verify that you want to remove it permanently.

Book Won't Open

Your book won't open on your Kindle (5th Generation), or there's an error when you try to open a book.
Before you perform these steps, make sure that your Kindle is connected to a wireless network. To learn more, go to Connect to Wi-Fi.
There may have been an error with downloading the book. Remove the title from your device, restart your device, and then download the book again.

1. From Home, select the book or content to be deleted and press the left side of the 5-way controller.
2. Select Remove from Device.
3. From the Home screen, press the Menu button and select Settings.
4. Press the Menu button again and select Restart.
5. After your device restarts, navigate to your Archived Items, and download the book again

Delete temporary files in Internet Explorer 7. Open InternetOptions by clicking the Start button , clicking Control Panel, clicking Network and Internet, and then clicking Internet Options. Click the General tab, and then, under Browsing history, clickDelete.

Try Settings, Backup and Reset or wherever it is found.

There are several fora on the net, discussing the battery replacement for the Gobii ereader. It looks as if there is no service for this reader. Some people even say you should trow it away and buy a new reader.
I think it should be possible to open the reader and order a battery, as soon as you can get it out. Just use google to fine a replacement battery.
You also could visit a phone repair shop and ask them what it cost to replace a battery, but first check what a new one will cost, because in a shop it could cost more then a new reader.

Success

Most tablets are glued together, some have plastic connectors around the edge.
I could not find anything related to "Gobii" but I did find "Kobo"
https://www.youtube.com/watch?v=2SmYg4q9ai4

This video should only be viewed for reference, your device may be different and require different tools or pecedures to take apart.

TRY REBOOTING IT.

Contact Google on how to delete books.

I had this problem couple of times with plenty of books were 'locked' or 'corrupted'. It seems like the problems (always) happened after update.
Signing out (this will delete books from the device) and then sign in again (this will re-sync device to account's library) could solved my problem. Took a little while to reload all of the contents but it worked for me.
It seems like we can make it more simple by deleting the related books from the device (not from library!) and re-sync the device. But I haven't tried it since I don't rename files of books, then it would be harder to find which file is what book. Easier for me to 'clean' everything that reload it again.
Hope this could help.