Ender14

I am running Vista Home Premium 64bit. Due to compatibility issues and things
just not working correctly, I want to replace Vista with XP Pro. When I put
my XP disc in, the option to install XP is grayed out and I can't select it.
Is there any way around this?

My XP disc is so old it is not bootable, nor does it contain SP1. I would
just wipe the hard drive and use the boot floppy discs I have, but I don't
know if my antique version of XP will recognize my SATA hard drive.

Any help is appreciated.