Change MasterBoot Hard Drive to SlaveNon boot Hard Drive & Visa Versa

On my latest computer, I installed onto it, my previous computer's hard drive as the master-boot drive (which has 98SE on it and is small, only 2 gigs), and made the 40 gig drive that came with the computer, the slave to which I also installed 98SE on a parbreastion as well as Windows 2000 on another parbreastion. But, I have not booted this 40 gig hard drive up so long ago, I can't remember if it worked. I have not tested it since to see what OS I will get when it boots as the master.

I just purchased an HP Officejet 5510 and HP's proprietary software will only load to my master-boot hard drive, which is full, thus only loading the most basic utilities, which will not do.

So, I've decided to make the larger 40 gig hard drive the master, so that I can install the full version of my HP Officejet 5510 software on I, and prevent things like this from happening in the future.

If I make the master-boot hard drive the slave hard drive and visa versa through bios, and something goes wrong, can I just go back into bios and reverse it to the former setting, or, is there a better way of doing this?

Thanks!