Here's how you can delete all columns to the right of a specific column in Microsoft Excel:

1. First, select the column that you want to be the last column in your spreadsheet. You can do this by clicking on the column letter at the top of the column.
2. Next, right-click on the selected column and choose "Delete" from the drop-down menu.
3. In the "Delete" dialog box that appears, select "Entire column" and click "OK". This will delete all columns to the right of the selected column.
4. Finally, save your spreadsheet to make sure that the changes are saved.

And that's it! Now your spreadsheet should end at the column you selected, and you won't be able to scroll any further to the right. This can be a helpful way to keep your spreadsheet organized and prevent accidental data entry in extra columns.