Trying to update to El Capitan (can't download Sierra) Don't know what I'm doing wrong.

current system https://imgur.com/a/9Ocuu

I actually was very fluent in this stuff back around 10.5. I had a fully working Dell laptop. Then I did the mulitbeast/clover USB Lion install on this custom desktop I built. It worked so good I just left it, and I mostly use the windows side for actual work (autocad). Didn't want to screw with a stable build. But it's got to the point where flash can't be updated, and many websites won't load.

I can't seem to even load the usb installer. get the "can't find mach_kernal" error.

I used this method to make the usb https://www.tonymacx86.com/threads/unibeast-install-os-x-el-capitan-on-any-supported-intel-based-pc.172672/

Also, I get random kernel panics just trying to get back into this build, probably from messing with the BIOS.

Any help is greatly appreciated

tl;dr Can't boot into El Capitan USB installer