Converting to CAD 2000

How do I convert Rhino into the above format?

"CAD 2000" isn’t a file format I’ve ever hear of.
Do you mean AutoCAD 2000?

If so, use the save as command to make a DWG or DXF file, and make a new named export scheme with the conversion settings you want.

yes autocad 2000 and yes I can save it as a DWG but what options do I use?

It depends on what you want.
AutoCAD has no provision for NURBS curves or surfaces so they need to be converted to AutoCAD entities. You need to choose what the conversion will be. That’s why we have the named export schemes.

What will you be using the DWG files for? Your down-process use might suggest an existing export scheme that will be close.

My guess is the CAM Imperial or CAM Metric (for inches or millimeters respectively), export schemes will be close, but they both save to the R14 format. Maybe edit one of those and change it to AutoCAD 2000 format and see if they work for you.

If you are after 2d lines then save and modify the ‘2004 Natural’ flavour option (change to ACAD 2000).
If you are after solids then save and modify the ‘2004 Solids’ flavour option (change to ACAD 2000).