Good afternoon JPJOHNSON777,
Welcome to the Apple Support Communities!
I understand you are having an issue with the iTunes Store window popping up on the screen of your MacBook Air. To address this issue, I suggest that you restart your computer in safe mode and check your Apple ID account to make sure everything is up-to-date, since this information is used by the iTunes Store app. Then we will look at any login items that may be affecting the system when you first turn on your computer.
Quit all open applications on your Mac and shut down the computer.
Restart the computer in safe mode - Use safe mode to isolate issues with your Mac
While in safe mode - go to the Apple ID website, and confirm you can sign in with your Apple ID an password.
- In the Payment & Shipping section - click the Edit button and confirm all of the information for your account is correct. You will need to enter the expiration date and security code for the credit or debit card you have on file. Confirm that the billing address matches what is on your bank or card statement.
- Click the blue Save button when you are finished updating the details of your account.
- Scroll to the top of the page and click Sign Out in the upper-right corner.
Source: Create, manage, and use an Apple ID
Next, we are going to check the login items (applications that launch when you first turn on your computer) while still in safe mode.
- Click the Apple menu in the upper-left corner of your screen.
- Click System Preferences.
- Click Users & Groups
- Click the lock in the lower-right corner and enter the computer administrator password.
- Click Unlock.
- Click the Login Items tab at the top of the window.
- You will see a list of items that will open automatically when you log in - write these down.
- Click on each item to select it, and then click the minus button at the bottom of the list to remove it.
- Click the lock to prevent further changes and close the window.
Source: Set up users, guests, and groups on Mac
Restart your computer as you normally would. If the issue persists, reply back to this thread with any additional information that you can, including any messages that appear on your screen.
Take care.