You can install both. You chose a system when you boot. Then you can run the old windows system for certain programs, Linux for web browsing. Older XP programs that won't run on a new computer, usually.
Win7 obsolete Jan '20 will increase your population of computers exponentially! I just put Peppermint Linux on an old Toshiba Laptop that was still on Win Vista. Happy guy, computer works again & it only cost him $50.00 for my time. I have a nice old Dell laptop I am going to try your program...