We have a custom object "Business Scenario" which is a related list in Opportunity. If the Opportunity is closed won then we have to write the validation rule on the custom object in such a way that users are not able to edit this custom record once created only System Admin can edit this.

Hi Guys,

I am trying to create a validation rule where if I pick a country a state would be required.  
Can someone please help me out. (both fields are pick lists)

I am struggling with how to search with record id in lookup field? 
it is wastful to create extra field for the name and have auto enumaration for name 

I found an option to change search layout - add some other field there, but it still looks only for name ? is there any workaround? to me Record is explicit enough to find the record.