Desktop

You don't change the BIOS, you change the position of the drives in your case. The primary drive is identified by the connecting cable. You may also have to set the jumpers.

some continue to tap the F8 key while starting to boot...if successful you will see the menu to get into the bios. (be ye very CAREFUL with what you change, be sure to save & exit)

Are you trying to change the boot order?
Change from 1st boot Floppy+ 2nd boot HD0+ 3rd boot CD-ROM
To 1st boot CD-ROM+ 2nd boot Floppy+ 3rd boot HD0

If so press the F8 or Delete key during post & the BIOS screen should appear & navigate to the menu that lists boot order, usually advanced menu or one of it's sub-menus.

For example you have two HDD, on the same cable. If you look at jumpers on the HDD you can see one of this is set to master and the other is set to slave. If you want to change the order of HDD you simply change the jumper?s settings. The other case is when you have two HDD at two IDE connector. In this case you must put the primary HDD to IDE1 and the secondary to IDE2. In this case the primary HDD must set by jumpers to master. The secondary can be master or slave.

Simple answer is that you can not. What you can do is alter the Boot sequence but not the actual Boot drive. So you could have the Boot Sequence set to Floppy, CD/DVD, HDD 0, HDD1, HDD 2.

But no matter what you change the HDD with the active partition in Windows will always be the boot drive even though it may no longer boot. if you physically change its location.

As you haven't mentioned which type of System/M'Board that you have there is no easy answer generally you need to push the DEL, F1, F2 or ESC key depending on the M'Board or System maker, this should be in the manual that came with the system/M'Board if it's a white box system.

Col