Extra lines added by the editor
I am using PCTeX version 4.0 or 4.01, and when I open my TeX documents some of the lines come out double-spaced causing the file to typeset incorrectly.
The double-spacing bug is solved by installing the 4.0 editor update.
If you are using a later version and there are extra lines added, the file most likely was saved in a 4.0 version with the defective editor. You will need to remove the double-spacing with an editor that supports searching for carriage returns. Simply search for two consecutive carriage returns and replace them with one. In Microsoft Word you can search for "^p^p" and replace it with "^p".