[GTALUG] Questions for sys install

[o1bigtenor]

Greetings

Laptop my wife has been using a her computer is starting to have
occasional graphics issues. Its an all in one mobo but its also almost
7 years old so looked for a replacement.

BestBuy had some systems on sale for after Christmas so ordered an Asus desktop.

AMD mobo 6 GB of ram, built in wifi w DVD RW all for can $360 inc shipping.

Now comes the kicker. Wanted to set the uefi bios to boot from Cd-rom
so that I could use gparted to give myself some disc room to enable a
dual boot system (Debian testing being the flavor du jour). It will
NOT boot onto the cd-rom it says that an illegal modification has been
made to the bios and the next boot option must be chosen.

(There was zero material with this system. It boots and all but there
is nothing with it. Even the OS key is burned into the bios. There
isn't even a system sticker any more!!)

Any suggestions on how to get this system to boot onto the cd-rom
short of pulling the hard drive and replacing it?

TIA

Dee