Upgrade Windows 10 failed. Re-reserve windows 10
Form 29/07/2015, Windows users can free update his windows 7/8/8.1 to Windows 10 when you got this message:
Someone upgrade failed. I think it has some system files crashed. For example; "Error code 80240020", "We couldn't install Windows Technical preview" something like this.
Don't worry! You can manually do upgrade in you windows 7/8 system.
Start -> Accessories -> run -> CMD. the means open a dos prompt with administrator
Input a command: cd c:\Windows\softwaredistibution\download
Type a command: wuauclt.exe /updatenow
This stage, you will wait for system re download Windows 10 and check you system driver programs.
After re-reserve completed, you can click "scheduler" or "upgrade now" go head.
Try it, should be OK. You problems fixed.