表单文件不包含有效的XML.Form无法打开。在prolog中不允许使用内容

I'm using NetBeans IDE, I'm creating a JFrame and during work on my project the computer shut down. When I run it again and run NetBeans and enter to my project design mode, it pops up this message. So how to fix the XML file for the JFrame form? I'm using NetBeans IDE, I'm creating a JFram