My mouse port doesn't work

Hi,

Here is a link to a video showing how to replace the power port in your laptop. It is useful as it shows how to open the laptop, so that the USB port board can be accessed.

(I realize that a faulty power port is not your problem and that this video doesn't show your exact model variant but it should be close enough to be of benefit).

At 1:34 minutes into the video the USB port pcb is visible and hopefully can be easily replaced.

Here is an image taken from the video showing the USB port pcb.

(click on image to enlarge for better viewing)

Here is a link to a supplier of the replacement part.

It is not a recommendation to use them. It is merely shown to give an idea of the cost of the part. There are others online that may suit you better. Just search for Toshiba Satellite L855 -S5210 USB port board for results