What do you see in the logs when you try to delete it?
In order to see what is wrong with this site, you could use the node browser to compare another non-broken site with this one and try to identify if there are wrong properties/aspects/permissions/whatever.
Once you find what is missing, you can try to fix using scrips.
Maybe somebody tried to move site into another, I don't know, it was in 2012 year. And there are no more errors. I found all links according to this site in dataBase. And I set everyWhere creatore "admin" but unfortunately admin cann't remove it. And can I remove these records from dataBase from table alf_node. Or it can broke all my data?