<> causing full table scan

[BigP]

Hi list , In one of my queries if I use <> in where clause it is causing full table scan .  If i use "IN " (  ) it uses index . Actually if it is" <> " the it is doing hash join and if "IN" then nested loop . when i make opt_indx_cost_adj to 5 it starts using index again with <> condition . Is there a way i can cause it to use index ( yeah i can use hints . )  ? anything else .. -bp