Just loaded XP on a new formated hard disk a couple of days ago,the machine would not boot from the xp CD it must not be bootable,so I loaded win 98,(my win98 CD is bootable, looked at the XP CD clicked on set up and away it went loading on top of the 98 instal, bit long winded but it worked.
I recall windows 95,if you had a new formated disk you had to load dos on first,leastwise with the version of 95 CD I had.