If Anytime Oracle Database goes down abnormally, due to machine failure or server reboot, most of the times objects gets into "INVALID" state.
command to check the status
select object_name,status from dba_objects where status='INVALID';
if you see a lot of INVALID objects run the following command after login to SQL
../../dbhome/rdbms/admin
run following utility to recompile these objects
SQL>@utlrp.sql
