Q: Keychain login cannot be found to store

iOS does not run on MacBook Airs.

Keychain Access utility should allow you to manage keychains as long as you logged in as a an administrator.  It is in Applications -> utilities folder.

For the Mac App Store, the account tied with Apple Support Communities usually is the same one with the store.  If you have a separate account, you may need to go to http://iforgot.apple.com/   if you forgot the password for it, and can't get the right one to appear with "Show Password" using the system's administrator account.   Here's how to reset the system administrator password in:

Apple Article to reset the password for 10.6.8 and earlier, and 10.7 and later.

To identify your operating system go to Apple menu -> About This Mac.

Apple menu -> System preferences -> Users  or Accounts can tell you if the active account is the administrator account.

At some point, you may have reset your keychain to default in Keychain Access. That caused your login keychain to be renamed.

Back up all data before proceeding.

In Keychain Access, delete the login keychain from the keychain list. Choose Delete References when prompted, not Delete References & Files.

Triple-click anywhere in the line below on this page to select it, then copy the text to the Clipboard by pressing the key combination command-C:

~/Library/Keychains

In the Finder, select

          Go ▹ Go to Folder...

from the menu bar, paste into the box that opens (command-V), and press return. A folder will open. Rename the file "login.keychain" in that folder to something like "login-old.keychain". Rename the file "login_renamed_1.keychain" to "login.keychain". You can then close the folder.

Back in Keychain Access, select 

          File ▹ Add Keychain...

from the menu bar. Add back the file now named "login.keychain". If any of your needed keychain items are missing from it, also add back the file you named "login-old.keychain". I suggest you transfer any needed items from that keychain to the login keychain, then delete it. The transfers are made by drag-and-drop in Keychain Access. You'll need to enter your password for each item transferred.