End user deletes in NEHANET are soft deletes. So If an Account, Contact, Opportunity, Forecast, Quote, etc. is deleted, it is only marked for delete. The System Administrator can view the deleted records under Settings->System Administration->Deleted Records. Pick the module to see all deleted items for that module.
The System Administrator can then either restore or permanently delete the soft deleted records. Once permanently deleted, the deleted records cannot be restored.
It is recommended that the System Administrator periodically permanently delete the soft deleted items to keep the waste basket clean.