How to set up a dual boot on a thinkpad

[joe at actionline.com]

I have a used Thinkpad T60 with win7 installed and I want to install
Kubuntu in a dual boot, but I'm having trouble trying to shrink the win-7
part of the 100-gig HD as as small as I'd like to make it. There are a
couple of nuisance files stuck at about the 75-gig point. I've tried
everything I can think of to get rid of those files, to no avail.

So, I think there is a reserve copy of win-7 in another partition. What is
the procedure to do a fresh re-install of win-7 from that reserve
partition so I can shrink the HD and install Kubuntu in a dual boot?