可以添加基本的新SQL Server索引会产生更多问题吗？

I'm completely new to Indexing and would like to speed up some of my customers systems. My organisation made a mistake and upgraded a few of our customers from SQL Server 2000 to SQL Server 2008 before testing it fully in-house. The (new) servers are running slower than ever before as result. This is baffling the customers as you can imagine. Each customer has a two SQL Server user databases set up both about 1GB in size and each customer has about 30 users each.I'm completely new to Indexing and would like t