Hi,
Please do try these troubleshooting steps that may help in resolving the issue.
- Do a hard reset, remove the battery and AC adapter then press and hold the power button for 20 seconds and see if it would get pass the update screen.
- If these doesn't work try loading it into Safe Mode, while the laptop is on the Toshiba splash screen repeatedly tap on F8 as fast as you can until it loads Advanced Boot Options.
- Select Safe Mode and press Enter, once in the desktop screen go to Control Panel and then Programs and Features. Click on View installed updates on the left pane.
- Uninstall any recent update you can see on the list then reboot your PC.