Error messages

To whom it may concern,
I am a complete novice and have been experiencing difficulties with wordpress since I started testing it out. Now I am receiving error messages every time I try to edit images with elementor. I clicked on visit dashboard, then on page then edit with elementor. A popup box appears with the below message:

the preview could not be loaded
we’re sorry but something went wrong. click on learn more etc etc

I enabled safe mode another popup box stated that the editor has successfully loaded? The issue could have been caused by one of your plugins or theme.

I disabled all the plugins that didn’t work and tried other themes which also didn’t work. then i clicked on click here for preview debug; and this error message appeared:

Warning: require_once(C:\xampp\htdocs\testsite/admin.php): failed to open stream: No such file or directory in C:\xampp\htdocs\testsite\index.php on line 10

Fatal error: require_once(): Failed opening required ‘C:\xampp\htdocs\testsite/admin.php’ (include_path=’C:\xampp\php\PEAR’) in C:\xampp\htdocs\testsite\index.php on line 10

I have also seen the below word press video and i still am unable to rectify the problem.
https://docs.elementor.com/article/245-preview-could-not-be-loaded?utm_source=editor-panel&utm_medium=wp-dash&utm_campaign=learn

I require step by step instructions

How do I fix this?

Thankyou Kindly

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