So if its pretty much a NEW system, with old harddrive, you can TRY and just sticking it in there... but it may be unstable. You MBD may have special chipset drivers for its controllers (PCI toPCI, PCI to AGP, IDE, ect). So you may need to get the drivers for this specific MBD for the specific O/S. I would try and get all the needed drivers (sound, vid, modem, NIC, MBD) first. Good luck, 'cause if it doesn't go smoothly it can be a real nightmare to get it working.
If you argue with an idiot he will drag you down to his level and beat you with experience.
I am not a fast writer.
I am not a slow writer.
I am a half-fast writer.