How do I fix this?

https://reddit.com/link/1li78kf/video/q51cj8t0ml8f1/player

I've had this guitar in my closet for the last two years. It was my oldest brother's, so we've had it for at least fifteen years. I like the feel of this guitar and how it looks, but when I plug it in, it makes this horrible buzzing sound. It makes this noise no matter which setting the switch is on, and when plugged into an amp, it is FAR worse. From what I know, it's a Canvas cTF red solid body electric guitar, with an HSS pickup set. So my question is: What do I have to replace on the guitar to fix this?