I've run into many problems trying to solve my 100% disk usage problem. I found that the Superfetch service was causing the issue, and that running chkdsk /s /f could fix the problem. I tried that, and it hangs at 12%, and the computer restarts itself after about 2 hours. So that leads me to doing a sfc /scannow, which tells me it found corrupt files and was unable to fix some of them. So I was attempting to do DISM /Online /Cleanup-Image /RestoreHealth, but ran into an error there.. the error 0x800f0906, the source files cannot be downloaded. I don't know what to do now. Somebody sort this out for me If logs are helpful, ask for which ones you need and I will post them.