Does by reducing the blank rows and columns will reduce Excel file size

I have a 34MB excel file. How can I reduce the size of it. I have blank rows from row 110-65536 and blank columns from col V-IV which I want to delete. I tried selecting the last row, then CTRL+SHIFT +DOWNARROW followed by DEL but it doesn't seem to work since the scroll bar at the right is still tiny which means that there are endless rows below. Why can't I simply delete them.

I don't think so. The file size can be reduced by reducing data. If you are having charts or images inside the sheet then it makes it more heavy. After you delete it, you'll need to save, then close & reopen the spreadsheet.

When you do that, instead of hitting the delete key, right click on any of those rows and use the Delete function. Same thing with the columns, select V and shift-control-right then right-click the V and use that Delete function.