You can get new document with all lines (not) containing some string: if you want to remove all lines beginning with "*" search for "^\*" (enable regex), check "copy non-matching" and press "copy".
If you want to delete multiple lines between some expressions, you must use other tool or plugin. -- <http://forum.pspad.com/read.php?2,60205,60212> PSPad freeware editor http://www.pspad.com
