Ghost 12 Copy command and SET DRIVE ACTIVE

I am trying to upgrade from an 80g to a 500g hd. The hd has been installed. I can do the "COPY" command to this HD and it works when I click copy MBR but I don't click SET DRIVE ACTIVE. Everything appears to be there. I then unplugged the cables to the 80g and plugged the 500g into the SATA0 port. No bootable drive was found. Ok... this is kind of what I expected.

 

My concern is this - this computer is critical - it's my source of income (self employed). I have back ups up the ying-yang... but I'd rather not be hit with any adverse situations. So my concern is this - What happens if I do the COPY, select copy MBR and SET DRIVE ACTIVE? What ACTUALLY happens? Does it make the 500g now bootable? I assume so but want to know so. More importantly does it do ANYTHING to the "boot" status of the 80g???? The reason for this is - if it makes the 80g non-bootable and I go to try the 500g and for some reason it doesn't work - now I am dead in the water!!!!!! Unfortunately Norton only provides an OPTION list and does not explain the ramifications of these options - I would think this would be clearly spelled out - what happens with the original HD!

 

Also no mention is given about what if anything I need to do in my BIOS settings. Do I need to turn something off/on there?

 

I can't risk doing this until I KNOW (please, not to offend - but don't respond if its just an opinion - I need to know) that if the new drive for some reason doesn't boot that I can still (re)plug in my current HD and continue on.