Dual booting with 2 seperate hard drives

Hi, have hp laptop in which I have installed seperately 2 hard drive which runs Windows 10 Proff. And Windows 7 Proff. These have to be installed to the same bay, independently, when they will be recognised. Recently I obtained another dvd drive bay in which I installed the second hard drive which runs Windows 7I have not tried to see if the bios will recognise them this options, do not want to loose the boot partitions, will the bios recognise the hard drives as drive C and drive E or drive D which the dvd drive will have been previously and will be again when I swap the dvd drive back, A lot long-winded question for someone to help and advise about. I previously have lost the boot sections of hard drives and I do not want to loose any on these drives. Thanks Dave

What ever drive the o/s boots from normally become c even if when booting from another drive its d or e are you going to boot by changing the boot order in the bios?

pevers3 said:

I have not tried to see if the bios will recognise them this options, do not want to loose the boot partitions, will the bios recognise the hard drives as drive C and drive E or drive D which the dvd drive will have been previously and will be again when I swap the dvd drive back

BIOS does not assign drives letters. The OS assigns drive letters when the OS loads based on the GUIDs assigned to the drives - which is stored on the drives themselves and does not come from BIOS either. You won't be changing the GUIDs of the drives, therefore when the OS loads, it won't change the drive letters from what they were previously either.