Uploading an excel data

hello all,

i am having an excel document containing some data in arround 25 columns.

<b>i didn't know the size of the file.</b> <b>the data varies</b>. it is of square matrix, may be a 2 X 2, 4 X 4, 8 X 8 or 16 X 16.

Now i have to update this data.can anybody explain how can i do this.

Regards