It won't turn on

Hi,

Try the following,

Disconnect the charger (if connected), then remove the battery from the laptop.

Press and hold the power button on the laptop for about 15 seconds then release the button.

Reconnect and switch on the charger (leave the battery out at this stage).

Start the laptop by pressing the Power button.

If the laptop starts, allow it to boot all the way to the Windows desktop. Allow it to 'settle' for a few minutes.

Then shutdown the laptop in the normal manner.

When the laptop has fully shutdown, switch off the charger and disconnect it from the laptop.

Re insert the battery into the laptop, reconnect and switch on the charger, then switch on the laptop.

Allow the laptop to boot all the way to the Windows desktop.

When it has finished booting and the Windows desktop is displayed, check the charging state of the battery. If it is charging allow it to fully charge before switching off the charger and disconnecting it from the laptop

Here is a link to the Ifixit guide on how to remove the battery in your laptop.

Toshiba Mini NB505 Battery Replacement

Hopefully this is of some help.