Hi Ross and welcome to the forum.
I am no expert I am afraid with computers, but it seems to me that the version numbers are the problem. Your original one ending with 950 is the most recent version. If you can find the original copy of the file and install that on the new computer, you should be right. When you transfer this file, assuming you can find the original download, it is essential to right click the EXE file and select 'Run As Administrator'.
Exporting to 3DS is not a viable option as the file would no longer be editable, except for textures.
Personal Architect is another, probably better, option. PA will be a much later version, so should open your original file without any problems. Being a later version it will also have many other enhancements. If you decide to upgrade to PA, make sure you install it by selecting the 'Run as Administrator' option.
All the best