Prevent Stylesheet Being Picked Up

Is there anyway to stop WordPress picking up a stylesheet? Let me explain…

I have a header created and looking / functioning perfectly. I then decided that I wanted to move the content of that header (and the styling) into the ‘page’ of my site, but as soon as I did that it started picking up styles in the main style.css stylesheet and it looks entirely different to what it needs to. Is there anyway to omit that stylesheet from being picked up on that page? Or to ONLY use the styles that I need.