Hi Geoff, welcome and thank you for your question. My name is ***** ***** I am glad to assist you today.
I am very sorry about your issues. What version of Windows is running on this problem laptop? Is it Windows Vista, 7, 8, or 10?
Also, when you turn ON the laptop, is the Toshiba splash screen (The POS screen showing Toshiba and its slogan) showing just fine and the problem starts when Windows is loading?
Please let me know by replying to me here so that I can help you further.