Using old hard drive with windows 7 installed on new PC with windows 8.1

[SpookyKid94]

So I'm building a new PC for my girlfriend, it's going to use an ssd as a boot drive with Windows 8.1 and have a separate 1TB hard drive for data. She wants to keep her old hard drive's data intact, but it has Windows 7 installed on it, so I don't really know how to go about doing this. Straight transfer to the 1TB seems redundant and I don't want to spend a week copying the important stuff to discs. If I just plug it into the new rig and put it low in the boot order, will I be able to access what's on it without screwing things up? A friend suggested partitioning the os before I move the drive, but I don't see what this would accomplish.

Suggestions would be helpful

 

[USAFRet]

She wants to keep her old hard drive's data intact

Define 'data'...

Applications? No.
Data such as docs/music/video/etc....probably. You may run into permissions issues, though.

 

[SpookyKid94]

Define 'data'...

Applications? No.
Data such as docs/music/video/etc....probably. You may run into permissions issues, though.

I was planning on uninstalling any programs before the move. Should I worry about the OS, though? I don't want it conflicting with the new system.

 

[USAFRet]

Define 'data'...

Applications? No.
Data such as docs/music/video/etc....probably. You may run into permissions issues, though.

I was planning on uninstalling any programs before the move. Should I worry about the OS, though? I don't want it conflicting with the new system.

Save any personal data elsewhere. SD card, external HDD, cloud (dropbox?)....
Wipe that old drive and copy things back.

If I just plug it into the new rig and put it low in the boot order, will I be able to access what's on it without screwing things up?

Yes, but you may run into permission issues.