I'm assuming that's the MSI-file? Right click, and look for "run as administrator" in the context menu. If it's not there, I have to assume that you indeed don't have admin priveledges on that computer, and you should talk to somebody that does.
The .msi also does not add/change anything in the registry as far as I remember.
But as many suggested above: If you like to install Orbiter on your companies machines and you don't have administrative rights there : use the ZIP