Get a copy of SentryOne Plan Explorer. It's free. Anonymize the plans (it'll clean the query & everything) and then post those. Otherwise, everything everyone is saying is just random stabs in the dark. You can't get good assistance without providing us with information. With no information, it could be anything.
"The credit belongs to the man who is actually in the arena, whose face is marred by dust and sweat and blood"
- Theodore Roosevelt
Author of:
SQL Server Execution Plans
SQL Server Query Performance Tuning