ChemDraw keeps accessing the A or floppy drive no matter what I do.
Have your serial number and registration code handy.
For ChemDraw version 4.0 and greater, go into your Windows directory and delete a file called "chemdraw.ini". Launch ChemDraw, and reregister when prompted.
For ChemDraw 3.5.1 and below, return "WIN.INI", which is located in the Windows directory, to its original state by removing the "[ChemDraw]" section. Use NotePad or another text editor to edit this file. As an extra precaution, make a copy before editing the file. Once you have removed the [ChemDraw] section, save the file, restart Windows, launch ChemDraw, and reregister when prompted.