don't start after upgrating to window 10

As it’s had been over 30 days since you installed Windows 10, you will need to perform a clean install of Windows 8.

To do this you will either need to have the installation disc that came with your PC (or when you bought Windows 8), and the Activation code for Windows. This can usually be found on a sticker on your laptop or PC, or with the installation media.

If you can't find the discs, then don't worry, as Microsoft offers Windows 8 ISO files for legal download. ISO files are disc images that can either be burned to a DVD, placed on a USB stick or run natively, as if the disc was inserted into the PC.

To download the Windows 8 ISO, you'll need Microsoft's Windows 8.1 Download Tool.

Once downloaded, this tool will allow you to download Windows 8.1 and make a bootable USB stick with it on. You can then restart your PC, boot from the USB stick, and reinstall Windows 8.1.

Hope this info helps.