In word 97 thru 2003, I was able to do this. Word 2007 won't let me. agghh

I'm in a text file, I hold down the alt key, and I select all the text to the right of column 40. I start at the top and select the entire file, scrolling down to the bottom of page 10. At this point all the text in the file to the right of column 40 is highlighted. In earlier versions, all I had to do was hit the delete key and the text was gone. In 2007, hitting the delete key only moves the cursor back to column 1 of the first line that I had selected. If I select all the text to the right of column 40, but only in the lines visible on the screen, the delete key works. It's when I let the cursor scoll the file up to select more lines that the delete key won't work. So, I've been selecting and deleting text one screen at a time, which is a real pain on a file with 75 pages. Can this be fixed?