Dont confuse RDisk with Disk.
Your disk etc has remained the same, the RDisk value represents the boot sequence set in your bios so previously when rdisk =2 your boot sequence may have been something like: -
CD-Rom
HDD
and after CMOS reset it may have defaulted to:-
Floppy
CD-Rom
HDD
More info can be found here: -
meaning of "rdisk()" in boot.ini file