Post, but no boot

I have a Dell XPS D333 running Windows XP Professional
(free academically). It posts (shows ram, then says that
devices are loading) but stops after the line :
ATAPI Device: NEC CDROM DRIVE
If I remove the hard drive it gets to the same spot, but
afterwards says:
System Configuration Data Updated
But since this is said every time, I think that it isn't
actually updating system data, just saying that it is.
Also at the bottom of the screen it says the junk about
the Del key and startup, but nothing happens when I press
Del continuously. Please note that I have wated upwards
of an hour for the computer at this stage, so I know the
hang is not just temporary.
Windows has booted properly before, but the cause of
this is (I believe) my nephiew loading a "Jimmy Newtron"
game on to the computer, but am not quite sure.
I have tried booting with the Windows XP cd and Windows
98 cd, but nothing happens except the revving of the cd
rom drive. I have tried windows 95 boot up disks, and
the XP boot up disk solution on the following website:
http://support.microsoft.com/default.aspx?scid=kb;EN-
US;305595 as referenced by this website:
http://support.microsoft.com/default.aspx?scid=kb;en-
us;314503&Product=winxp .

Thanks for looking at my problem on this old computer,
any help will be apprecited by my nephiew.

Ben Enfield