>>Did you try to recompile it? E.g. is it a stored procedure or just a statement? If the latter, try playing with the options OPTION (RECOMPILE) or OPTIMIZE FOR UNKNOWN
>
>I added that to the command and clicked on Display execution plan. It is still the same thing.

You can force usage of a specific index, but normally it's not a recommended approach. Is the query very complex?

Are you running in development environment where you can afford to get rid of all plans?