Regression Analysis On 1000 Sheets

I have approximately 1000 worksheets, each containing data that a regression analysis must per performed upon. The data is in the same columns on all sheets. The problem I'm facing is that there are frequently rows containing blank cells that I want to eliminate from the regressions, and these rows are different for the various worksheets. Obviously, a macro is needed to avoid manually analyzing 1000 sheets. I understand how to use With..End With to accomplish a regression across all the sheets, but does anyone have suggestions about how to filter the rows on each sheet to eliminate the blank cells?
Thanks for any help,
Ken.

I just answered my own question. The ISNUMBER() function eliminates the problem when either or both of the cells in a particular row are blank; regression ignores blank cells.
Ken.