On several occations, I have faced the situation that the default.aspx page on a Site doesn't work. More specifically, a reference to a WebPart and/or Control is throwing a error because the assembly is not found. Fine, you just fire up the dreaded SharePoint Designer and remove the dependency line. However, if I wanted to use this method when not having SharePoint Designer, how could this be done?
EDIT: Removing the web part using the "?contents=1" web part management page didn't help in my case. The <%@Register tag was still there and had to be removed using SharePoint Designer.