Tip: You can restore a user from Active Directory Recycle Bin with PowerShell.
# The Recycle Bin has been introduced since Windows Server 2008 R2
# The forest functional level has to be at least on Windows Server 2008 R2
# Once you enable the Recycle Bin, you can’t revert back (irreversible)
To enable the Recycle Bin (admin rights required) :
1 |
Enable-ADOptionalFeature -Identity 'Recycle Bin Feature' -Scope ForestOrConfigurationSet –Target (Get-ADForest).Name |
Delete (to Recycle Bin)

Restore (from Recycle Bin)
1 |
Get-ADObject -Filter {SamAccountName -eq 'sPowershell'} -IncludeDeletedObjects | Restore-ADObject |

Note: To do that with GUI (Windows Server 2012) :
Server Manager > Tools > Active Directory Administrative Center > Domain > Deleted Objects > Object (Restore)