My toshiba is stuck at 55% when restoring to factory settings. What should I do ?

Hi,

That doesn't seem normal for a Factory Reset to take that long. Please just redo the Factory Reset and if the same problem will persist I would suggest getting a new set of Factory Reset disc from Toshiba.

Here's where you can order online a Factory reset disc.
https://support.toshiba.com/repair

But if you've already tried running a factory reset disc and you got the same problem then the HDD should be replaced already since it's the one who's causing the lock up when installing Windows.