Used a laptop cd at the beginning?

My laptop won't start it always gets stuck in the loading screen, I downloaded windows 8.1 onto a cd and I could open it somehow

Put it in the drive and restart then it starts up.Iso files are not designed to be opened.

If you use Win 8.1, it would make sense to use one that fits your operating system.

Windows 10 got another update out, it broke my whole laptop

Yes and?