chopping the corners off a block

[micheus]

About the attachments, we have a small room for that. It's most intended to attach small files like the dump files (log of acrash). I do recommend you to use the http://www.photobucket.com/ - then you can use the button in the post editor to access it.

About you problem, it look strange you are extruding a face to create a shape that you want to remove after.
Anyway, if I understood right what you need is to Dissolve [Back Spc] and then select the two vertex in the bottom - left of the removed faces and use Connect.
Try that.