In that case it sounds like ACR isn't properly installed. I'd uninstall Photoshop and reinstall. Watch the CC desktop app and check that ACR gets installed with Photoshop.
It could also be that your file associations are broken. Check in Windows that cr2 is set to open in Photoshop, and if not set it (Default apps > choose default applications by file type).
EDIT: try the file associations first, if that doesn't work uninstall/reinstall.