It will most likely be a troublesome process. A solid, thorough route would be to:
1. Back up any data; if you cannot back it all up, there's still hope
2. Do the hardware replacement (I'm not going to list all that, since I'm assuming you know how)
3. Reinstall the OS, and a "windows.old" file should be created, including all your old docs, downloads, pics, programsx86, programs, etc.
4. Install the new drivers, and once you're done taking things out of windows.old, or from your backup, delete windows.old
All set! That's what I did last week.