First, you should delete all you indexes and create structural compound index. It's open automaticaly any time a table is open. There's no good reason to use any other type of indexes as a permanent indexes for a table. There's how structural compound index can be created.

USE mytable EXCLUSIVE
INDEX ON filed1 TAG filed1 ADDITIVE
INDEX ON filed2 TAG filed2 ADDITIVE
INDEX ON filed3+filed4 TAG f3_f4 ADDITIVE

Second, Read 'Using Rushmore to Speed Data Access' in the help or at http://msdn.microsoft.com/library/default.asp?url=/library/en-us/fox7help/html/dgusing_rushmore_to_speed_data_access.asp to understand how indexes could speed up your queries.

>Hi everyone,
>
>I have 2 index file and I use SQL select to make a query but they don't optimize (I check with sys(3054,1)), here is my code :

>sele 1
>use customer inde cust1.idx && inde on cust_id
>
>sele 2
>use sales inde sales1.idx && inde on cust_id
>
>sele s.cust_id,c.cust_name,s.sales_qty from customer c, sales s where s.cust_id=c.cust_id order by s.cust_id into cursor tmp

>Anyone knows why this is happend and also it doesn't optimize if I have more than one field on index file (i.e : inde on cust_id+cust_name to idxname)
>
>TIA,
>
>Budianto