Get a new SATA drive Well, you can actually use the old HDD.
My suggestion would be: clean install your XP in the new system, I always recommend this if we get the new mobo. A little pain in the start, but better do this in the beginning to save more headache in the future. The reason is that for some reason Windows can not 'cleanly' remove all previous unnecessary files/drivers/registry etc. I'm not a Windows Hacker/Cracker/Guru or whatever, so the easiest way for me is to clean install Windows.
I'm using IDE optical drive under ABiT IX38 mobo, and I can perform a clean install using my IDE optical drive, which means that the IDE on JMicron runs well. And you're supposed to be able to do clean install as well.
One note: you should take a look into master/slave configuration for both of your IDE drive (HDD & optical) since you're running on one cable. X38 mobo will only have one IDE slot I presume. Well, guess you've already done this since you're able to start your computer (into Windows).
The other workaround on this that I can say (but I'm really against it) is: see if you can load into safe mode. Uninstall any old driver, then restart, then install all your new mobo driver from the CD that came with your mobo.