I am using LT2010, and am having a problem inserting blocks.In former versions of LT when you attempted to insert a block into a drawing, and a block with the same name was already in the drawing, a prompt came up asking if you wished to upgrade the existing block to the new block configuration. In LT2010 this prompt does not come up, and when you insert the block it automatically downgrades the new block to conform to the configuration of the block which was already in the drawing. I looked at all of the system variables to see if there might be one covering this, but couldn't find anything which might be controlling this.Does anyone know how to get back the prompt?

Hello, in old Autocad release ( even not LT ) when you were inserting a block already existing in the file you had'nt even the choise; the block inserted was updated with the one existing.
May be it's was is happening with your LT 2010.
If all the command existing in the "full" release were existing in the LT, then nobody would buy the x 3 expensive "full" releases.
 
Anyway, it's possible to insert a block that you want to update conformably to a one in another file:
You insert it "exploded" and "remake" it in the file with the same name, scale, rotation, insertion point etc...
For this I keep in a part of my file some kind of a "block library" including an example of each block with a line attached to the insertion point and with a simple line text of the exact name of the block.
With ctrl+c / ctrl+v on the texts you can easily remake any block with no confusions even with complicated and/or long names.
Realy old Autocad releases such as the R14 don't accept block names with spaces and more than 32 digits.