If it's XP, you can perform a "Repair Install" so that your old hard drive will boot with the GX270. Alternatively, you can install a third-party IDE card, but the drivers have to be installed in Windows before the drive is moved over.
I move hard drives from Windows to Windows regularly using the latter technique, but support for XP is going away and I'm finding that XP x64 isn't properly supported on my newest machine (an XPS 8500). Note that support for XP is ending in less than a year, so you're well-advised to consider a new version of Windows. (I think 7 is the last version supported for the GX270.)