A friend asked me to help with his old HP Pavilion a1213w desktop.
It was running very poorly and sporadically. I spent a couple days cleaning it and eliminating all un-essential Apps and startups, improved, but still not good.
After discussing with him, we agreed to reformat and re-install XP Home.
I've done this MANY times years ago, but haven't messed with XP in awhile.
I have my original XP and key that I agreed to give him (it's not installed anywhere else).
I pulled his HDD and connected it to my Win10 laptop as an external USB drive and performed a quick reformat. Then I tried to bootup the XP CD and I'm getting a message: OS wasn't found. I expected this, but I also expected it to boot to the CD. I get a generic BIOS screen with ESC & F10 options, but It doesn't seen to be responding to the keyboard at all.
Am I overlooking something?
Also, do I need to re-format the drive as bootable? (how can I do that from WIN10 / usb external?)
I seem to recall working on HPs in the past and they had some nuances that made them problematic to deal with. Any pointers?

Thanks!