its both a 64-bit and a Windows 7 issue.
AutoCAD 2000 uses a 16-bit installer from what I remember which means no go for 64-bit
If you were using Windows 7 Professional 64/32-bit then you could get around that by downloading "XP mode" for it and would most likely be able to get it to install/run.
If you re-install Windows as 32-bit, with Home premium, you could try the "troubleshoot compatibility" option when right clicking on the setup.exe file and run it as if it were XP but I'm not sure how(or if) the program would run in that case.
If you go to Autodesk for help all you'll get is "Buy 2010, it is the only one windows 7 supports"