Well, I was confused by what all you were talking about in your first post. But let me just ad what I can.
You cannot install windows on to a hard drive using computer "A" and then hook that hard drive up to computer "B". It has something to do with the BOIS's of the computers. You claim you once had success doing this, to which I can only say the two computer's must have had freakishly similar Motherboards/BIOS's.
If your computer will not load CD's from the CD-ROM itself, you're kinda screwed. I have that exact problem. I've even tried switching boot device order, switching jumpers on the CD-ROM, and even swapping another CD-ROM with the computer: my BIOS simply will not run a CD-ROM without a CD-ROM support program like the Win98 Boot floppy has.
Now you claim to have a blank hard drive, and your computer will automatically go into DR DOS when you turn it on?
If I've interpreted that to be true, than what you have is a BIOS with a specific free version of DOS written into it. That's more than I have in my BIOS. But it's not enough.
You cannot run the WinXP setup.exe file while in DOS mode. I've been told it has something to do with DOS not being able to understand NFTS. I don't know if that's true or not, I just know DOS will give you "this program cannot be run in DOS mode" when you try to run the Winxp install/setup file.
My solution was to download a program from Microsoft that extracts itself to 6 floppy disks, and you can use these floppies in order, and then it says "please install the Windows XP Installation CD" and that will get Winxp installed.
The problem with this is that you have no floppy drive. If you're computer can't read from the CD-ROM, and has no floppy, you are screwed.
There's only two things I can think of.
1. Hook somebodies floppy drive into your motherboard (and pray it works).
2. from your DOS prompt, install win98 from your CD-ROM. From Win98, pop in the WinXP CD and attempt to install. You might not be able to get a full install; but only an "upgrade". Hopefully it will allow you to erase win98 and do a fresh install of WinXP.
The only other thing I can think of is to find some kind of multi-OS-installation software that actually allows you the option of installing a variety of Operation systems. I know there are multi-boot software programs that allow you to choose which OS you want to boot from, but I don't know if any of them have a self contained installer program that actually allow you to install different types of OS's.
If you happen to find such a program, please let me know, because I could really use it.
Oh, most of these multi boot programs are floppy disk programs, so you'll have to stick 'em on a CD and then use your DR DOS to install 'em from the CD. They should be able to run in DOS mode.