A: I added a SharePoint Web part to my page, and now, when I go to the page, all I get is an error message. To get the page working again, I need to delete the problem Web Part by doing the following:

Go to the page with the error and add

?Contents=1

to the end of the page’s URL. If the URL already has a “?” then add this instead to the end of the URL:

&Contents=1

You will now see a list of all of the Web Parts on the page and can now delete the offending Web Part.

Here is an example for a site URL that ends in aspx:
http://……./default.aspx?Contents=1