ntldr is missing

[s.roman]

whenever I try to boot my computer from the ubuntu cd, or
smartbootmanager floppy I recieve the message "NTLDR is missing. press
ctrl-alt-del to restart". Does anyone know what I'd have to do to fix
this? I checked around the computer and I'm fairly positive it doesn't
have anything to do with the hardware. My specs are 2 PATA 20gb hard
drives, pentium 3 1ghz, 512mb ram, Geforce 2 GTS. It's a HP Vectra
VL400 MT according to the label. I'm not sure what motherboard model
it has, but it is an intel 815 chipset. Any help would be appreciated.

Roman