I have Windows 7 for system builders. It doesn't contain any MS office software. So I downloaded this free LibreOffice software. I was going to install it today.. The RUN or installer box is labeled with security warning. "This file type can potentially harm your computer. Only run software from publishers you trust." I ran a virus scan of the download and it didn't return anything. Did it give me this message because it is an open source application? Should I not install it? I don't buy Microsoft products anymore.