select ' exec sp_rename '''+ name + ''' , ''zOLD_'+name +'''' from sys.objects where type_desc = 'user_table' and name not like 'zold%' order by [name]
name - actual table name
changed name will be zOLD_[TableName]
selected from sys.tables, alternatively u can select it from sys table
execute this query and copy the result into new Query analyser
and here is script that will do the disaster.