it is very important to backup the contacts with both computer and cloud service. or it would be hard to recover themIf you have sync enabled your contacts are safe. Go to contacts, menu button and hit import/export. Now try to import from SD.If that doesn't work go to contacts, menu button, accounts, manage accounts, select your gmail account, sync contacts.The third way is to use some data recovery software to recover deleted contacts from android with one click. Good luck.