The only way to convert these files to version 7.0 is to first save them as 7.1 and then open them up in version 7.1 which can then save them as 7.0. If you don't have a copy of 7.0, then if you post the VIs, someone may do the conversion for you. If you have used anything in the program that is not supported in an older version of LabVIEW, you will have to rewrite it. In the long run, it might be simpler to just upgrade the NT computer to something that LabVIEW (and Microsoft) supports.