"What do I do in Step 5? I have don't have any of the operating systems mentioned there."
Nothing, as Tom said if the folder is not there, you're out of luck.
"Also would I need to specify drive letter as I have dual boot setup with Windows 7 Ultimate 64 bit?"
There was no mention of a dual boot in your original post, was it there before, or only since someone fixed it and reinstalled?
If you didn't have a dual boot before and now have, then your original instalation is still there with all your settings. All you would need to do in that case is select the other OS from the menu at boot time.
I have the .old folders. Once I lost my Windows 7 32 bit and had to start from scratch, I decided to install Windows 7 64 bit on my second partition. My first partition is a new installation of Windows 7 32 bit over my old one. I still have the .old folders.