Thank you so much mate. Those pages really helped. Managed to do it. I had a go previously but I didn't look properly at the button options.Hi,
Plenty of information here, about changing default icons, for other windows built-in icons:
https://www.howtogeek.com/howto/13631/customize-your-icons-in-windows-7-and-vista/
If you are interested in creating your own icons from images, or want to install downloaded icons, see here:
https://www.howtogeek.com/65291/how-to-make-your-own-custom-windows-7-icons-out-of-any-image/
I hope that helps