Ideleted nook app

The device cannot be fixed.
Your information is another matter. Any book, music or app you bought will still exist in the account. Also, ANYTHING sent to the cloud will still be there.

All else you put on your Nook is gone unless there is a copy on a PC where it was originally.

If anything was transferred to a SD card, it is still there.

Barnes & Noble stopped doing APPS. they still do book.
Other books can also be put on you NOOK. Project Gutenberg now has over 30,000 free titles. You basically download onto your computer and read it using Calibre, a free e-reader. Or, then plug the Nook into your computer and transfer the e-book to your Nook. The non-B&N books can't be in the same place as B&N books, but you can make separate folders under My Files. For other books, if they are epub or PDF, you can read them on Nook. (Comic books are often in .cba, .cb7 which can also be read.) Some sites (Google Play and LULU for example) have multiple formats and it is not easy to learn which will work on your Nook.

For some books, downloaded from your PC, the only way to delete them is to attach the Nook Simple Touch to your PC and open the Nook Simple Touch on the PC. (For a PC, open the computer icon and look for the Nook icon and click on that.) From your PC you can delete files from the Nook Simple Touch or move them off the Nook Simple Touch to your PC.
IF you have a MAC or if my advice doesn't work, you should contact the Nook support. It is at the Nook website. Click on Nook and look for Nook support.

Did you download an app to read the ebooks? Such as kindle or nook? And there are generic app for reading too! You might go into google play to see if they offer a reading app. I don't know tour device but surely it has a place to go for apps and most have a reading app.

Steps To Change Font Size On Nook Tablet
Step 1: Chose a book that you would like to read on your Nook.

Step 2: Next, view the Reader Settings

Step 3: Tap the screen to expose the menu, where you will see a "Text" icon.

Step 4: After having clicked on the "Text" icon, you will see that you have the option to change the font size. There will be a letter "A" that will allow you to change the size. Click on the "A" and decide which font is best for you.

Step 5: Touch the main screen to return to your book.

If you still have any kind of problem then you can take nook color support from experts by calling nook help number. You can also navigate to www Nook com for more information.

A few items can only be read on a PC or Mac using the Nook Reader. Have your title, price, date, and book ISBN number handy. Then contact Customer Support for a refund.

Download all the archived and unarchived books and save them to your computer. Never deleted these.
You have two options for the archived books.
Un-archive them and they will appear on your nook and download as you see fit.
OR... Sideload them. Which is probably what you did before since archived books already disappear from your My B&N Library and would have had to be in your My Documents Library.
Not exactly sure what you mean by 'does not go to my nook' when you try and save/download from the website.

If still having any kind of issue then you can take nook support from experts or call nook help number.

In order to start using your Nook, you'll need to register it through the Barnes & Noble website - I've shared the steps below. Once you've registered it, you will be able to start purchasing and reading books. Please note that you will need to set-up a B&N.com account first. That is done on BN.com and simply click "new user account." Once you have set that up, follow the below Nook set-up steps.
NOOK Set-Up Steps

1. Charge your new NOOK 3G or NOOK Wi-Fi for 3-hours from a wall outlet using the Power Adapter and USB Cable packed at the bottom of your NOOK box.
2. Turn on your NOOK by pressing the power button at the top.
3. Connect to Wi-Fi.
4. Register your device by entering your BN.com account email.
5. Tap the down arrow button in the lower right corner of your color touchscreen.
6. Enter your BN.com password.
7. Tap Submit