Where on my pc does iTunes store the backup?
From Locate backups of your iPhone, iPad, and iPod touch:


  iTunes places the backup files in the following places:
  
  
  Mac: ~/Library/Application Support/MobileSync/Backup/
  Windows XP: \Documents and Settings\(username)\Application Data\Apple Computer\MobileSync\Backup\
  
  Note: To quickly access the Application Data folder, click Start, and choose Run. Type %appdata% and click OK.
  Windows Vista, 7, 8, 10: \Users\(username)\AppData\Roaming\Apple Computer\MobileSync\Backup\
  
  Note: To quickly access the AppData folder, click Start. In the search bar, type %appdata% and press the ↩ Return key.