my libre office items seems to have been hacked by something called openoffice. Does anyone know about this?
The question lacks any useful information to be answerable. I don’t think someone would be able to answer anything (apart of the fact that LibreOffice is based on OpenOffice.org, and there’s also another fork named Apache OpenOffice - see Wikipedia), without knowing what is “hacked”, what are “items”, what are you using (OS, LO versions, etc), and what you did.
For a guess, the file associations for LibO documents are now showing as handled by AOO; one possibility is that someone has installed AOO and the installation has reset file associations. However, a bit more information would help. What Mike said