Long time user, seldom required help. Updated to the lastest OS (2006) and all was fine.
Recently though, when I try to connect to a software respository, it times out and tells me "Can't update packages, show last known list" (or words to that effect)
I realize the 770 is old, but has the respository been abandoned and/or shut down? It still shows on the main page here....
I don't have my 770 handy, but I don't think the main repositories are down. I last updated about a week ago.
That is the message you get when a repository is not available though, so go through the list in Application Manager and disable them one by one until you figure out which it is. It's probably one of the specialized, minor ones.