Add Drop DEFAULT Constraints

select
'ALTER TABLE '+ quotename(t.name) +' DROP CONSTRAINT ' + o.name 
from sysobjects o 
inner join syscolumns c on o.id = c.cdefault
inner join sysobjects t on c.id = t.id
where 
o.xtype = 'D'
go

select
'ALTER TABLE '+ quotename(t.name) +' ADD CONSTRAINT '+ quotename(o.name) + ' DEFAULT (getdate()) FOR ' + quotename(c.name)
from sysobjects o 
inner join syscolumns c on o.id = c.cdefault
inner join sysobjects t on c.id = t.id
where 
o.xtype = 'D'
go