Unfortunately none of the responders or responses given helped solve my problem. However, I solved it by looking for files (mostly system) that were currently not being used and moving temporarily. I then discovered, that although the TurboTax installer checks for space on C:\ and won't run until it finds enough space there, once it finds that space it allows you to set the drive and directory so I now have TurboTax installed on D:\ , working just fine, and the moved files back in place.
