When you load another OS, it will automatically erase the existing xp install for you.
I cannot help you with a win 7 download, but I would expect it will cost you $ when you do find it.
if you use your pc for youtube, email,banking, facebook, messenger, skype, searching...google etc, playing music, storing photos, downloading info, music, movies ....blah blah.....
Take a look at Linux. Interested?....post the specs of your pc in the Linux area and someone there will take a look for you to make sure it will run ok...
The best thing about Linux......its FREE.
How to find specs
Condobloke ...Outback Australian fed up with Windows antics...??....LINUX IS THE ANSWER....I USE LINUX MINT 18.3 EXCLUSIVELY.
“A man travels the world in search of what he needs and returns home to find it."
It has been said that time heals all wounds. I don't agree. The wounds remain. Time - the mind, protecting its sanity - covers them with some scar tissue and the pain lessens, but it is never gone. Rose Kennedy