it is rare that you can successfully move win2k/XP between two different systems. The hardware layer is usually too different. So having installed XP on the hard drive in a different computer, and then moving it to the other system, generally is not going to work.
The only easy way to move an install, on a hard drive, between systems, is if they at least have the same motherboard. You probably would need to reactivate it if it does work.
You could use Ghost to clone the drive you are running now, and get it on the other drive if it is the o/s you need to use.
about 2 months i did change a hdd into another computer and went to bios and reset cmos and it did work but it migth not in your case
what's the new hdd o/s?
amd athlon xp 2400+
1 apacer 256mb unb pc2700 cl2.5
motherboard msi kt4av via kt400a chipset based
1 ??? 512 mb pc2700
1 agp 8x/4x (geforce 4 predator mx4408x)
2 year old 21 magnavox monitor
1 aquos sharp 15\"tv
Seagate 40gb hd
DC Output: 420Watts Total: +5V/0~42A, +12V/0~18A
+3.3V/0~26A, -5V/0~0.8A, -12V/0~1.0A, +5VSB/0~2.5A.