Does IDE internal hardrive needs formatting

Hello,

I have bought a new Desktop 80 GB IDE internal hard drive for my desk top. I am replacing this with the existing
old har drive. My question is will my computer recognise this hard drive when I turn the power on or
does it needs formatting before I put it on the computer.

I checked my product manual, it says max capacity Hard drive I can use is 80 GB (or 120 GB BTO)
I dont know what is 120 GB BTO is ?

Any answer will be appreciated.

Thanks...Ravi