Taking To Long To Display Excel Spreadsheet On Datagrid?

I have the following in my little program:A form containing a button and a combo box where each item is a "year" ex. 2009,2010,2011...
When the user selects an item from the combo box, and clicks a button, an excel spreadsheet is displayed in a datagrid.

- Depending on the item selected, a different file is opened.

Now, my problem is as follows. Every time the user press the button, it takes like 50 seconds to open the file and display it in the datagrid.

- The file range is from A1 to J393 (a lot of cells)

The procedure reads every cell from A1 to J393 and puts it in a multidimensional array. Therefore, I would like to know if there is a way to speed up this process.Another thing, lets say I selected year=2009 and press the button.I wait 50 seconds approx.Displays the spreadsheet (corresponding to the year 2009) on the datagrid.

Then

I select year=2010 and press the button.

Wait another 50 seconds approx.

Displays the spreadsheet (corresponding to the year 2010) on the datagrid.