First and foremost, what exactly do you mean by "everything stripped off
of it"?
If you mean to say that the HD, floppy drives (if any), CD drive,
motherboard etc. etc. is all stripped off then clearly you will be
better off buying a completely new computer from your local shop.
However, if the computer is still there except it lacks the operating
system then you can buy, borrow or even steal somebody's CD (and the
serial number if you don't have at the base of your system) and install
it from scratch. Some hobbyist normally download the OS from Piratebay
website with serial number but this is not advisable because you don't
have sufficient knowledge to clean it out of any spywares and viruses
let alone you may be highly ethical and religious minded..
You can borrow it from a friend or your neighbor and you can make it
work on your system by twicking JUST ONE FILE on that CD. All that crap
by "Most Valuable Pigs" to say OS is bios locked is exactly that -
CRAP. Ignore it because all CDs are identical in all material respect
(including those that are Volume Licensed). There is just one file that
is different and thankfully that file is a text file and can easily be
changed to suit your need.
Let me know if you need further help.