Grant Permission To Administrator Over System Files?

I've always loved the older version of Microsoft Windows Paint for Windows XP edition.

After some research, I learned that I could download that older version and replace it with the one I had on Windows 8.1 At first, I tried to replace it in the system32 folder, but it said,

"You do not have permission to perform this action. You require permission from TrustedInstaller." After researching the internet, I learned step by step tutorial on how to change the owner which was TrustedInstaller; learned how to grant permission to me; the administrator over the system files. It has been said, "You should be able to access that particular file or folder. Be careful when you alter the permission for System file or folder it may cause serious damage to your system and compromise security. So please create a system restore point[/URL] first and then proceed with caution."

My question is.....can granting full control to the administrator over system32 folder cause problems or issues? Is this wise to do?

If not, I revert back to granting permission to TrustedInstaller over system32 folder.

All I wanted was to replace mspaint.exe with an older version from Windows XP edition.