Can't boot XP after installing Windows 7

[detrunks]

Hi,

I've been trying to fix this for ages after scouring the internet to no avail!
I had 2 partitions on my hard drive - C and D.
C had windows 64 and D has XP
I reformatted C and installed windows 7 in it. Now when I start my PC I get the NTLDR is missing error.
I can boot to W7 if I keep the disc in but don't have the XP disc.
I understand boot.ini is not used in W7 - so how do I fix??

thx in advance