Hello - I think that the previous person that repsonded was almost correct but I don't think that you can simply assign drive letters in the device manager ala WinNT/2000 disk manager. He is correct in stating how the letters are assigned but I can clarify that the extended partitions on the master drive get assigned first then the additional partitions on the slave get whats left.
So how do you get your 4.3 to go in unaffected??...I would fdisk the drive down to blank. Re-fisk it and select option 1 then option 2 - creating only an extended partition on the drive. What we don't want is any trace of a primary partition on this drive. Format it and you now have a disk that will fall into line only after the master primary and master extended partitions are assigned letters. One thing left to do is to go back to the device manager and assign the letter of your CDrom to allow space for the 4.3 to get it's sequential letter without changing. IE if the 4.3 is F then manually set the CDrom to always be G. This way whether the 4.3 is installed or not, all the letters can be counted on being set in a static pattern...now gimme my points! :-)
Johnny!
