Adding a second HDD with an older OS already installed

So, I’ve currently got Windows 7 Ultimate 64-bit running on my main HDD. I'm looking to grab some files from an old HDD that’s still running Windows XP Professional sp3 32-bit and move them over to the new drive. If I just plug the old HDD into my PC case, am I going to run into any major conflicts? Or will the system just give me a choice of which OS to boot into, letting me just jump into Windows 7 and browse the old files like normal?

Is there any other way to handle this without all the hassle of swapping drives? I really want to avoid pulling out my new HDD just to plug in the old one to wipe the OS, then swapping them back and forth again just to get the old drive in there without the OS getting in the way. 😵

It’s really not going to be an issue—honestly, it doesn’t matter at all what’s sitting on your other drive. You just need to make sure you head into the BIOS and set that Windows 7 disk as the primary boot device.