For a more comprehensive and updated post, refer to How to recover deleted post (updated).
Recovering from an accidental delete
You have accidentally deleted some posts or links, etc., or you may even have messed up your template, and you need to recover from the mistake urgently. What do you do?
This is what you can do. Do a search (Google, Yahoo, etc.) for some terms in your past post and see if it turned up some cached copies of your post. For example for this blog, I did a search for “how to add addsense to your blog” and the result was this:
Blogger for Dummies: How to add AdSense to your blogHow to add AdSense to your blog. First, you must have an AdSense account. If you don’t have one, click on the button on the sidebar to the right that says …
bloggerfordummies.blogspot.com/2006/03/how-to-add-adsense-to-your-blog.html – 21k – Cached – Similar pages
Note that it is a cached copy and not the current corrupted copy. Copy what you need from this cached copy. If it is something in the template, do a View>Page Source to get the template. You cannot copy the whole of the source codes to paste into your template as it also contain the codes for your post/s. Only can only copy the relevant part of the source codes (for example, customization such as links) to make easy a transition from a corrupted or accidentally deleted template to a new template.
Alternatively, you may type in the full url into the search box and it should turn up most of your posts.
If you can’t find any cached copies in the search engines, another place to try is the Wayback Machine.