There are some instances where a SharePoint page does display the ribbon so you are not able to Edit the page, this normally happens if the page is a web part page and not a standard wiki page. There are two ways to Edit this page, use SharePoint Designer or just add the following [?] switch at the end of the URL as demonstrated below.
This should place the page in a design mode with Edit functionality
Other parameters that can be used are listed in the table below.
|Add Web Parts/Browse||ToolPaneView=2|
|Add Web Parts/Search||ToolPaneView=3|
|Shared Page View||PageView=Shared|
|Personal Personal View||PageView=Personal|
So if you need to edit the Shared view of the default page, add the following parameters after the page extension.
or if you wanted to Browse web parts and add them to your Personal view:
and if you use the following ?contents=1 in query string(URL) it will put the page into webpart maintenance mode, where you will be able to update or change a view of a webpart or even delete the webpart from the page.
This could help resolving issues if a page throws an error with regards to a webpart and does not load.