If you experience a problem with video output on your Toshiba Satellite 5105 you can use this disassembly guide for removing and replacing the video (VGA) board. First of all, make sure that the video problem is caused by the video board. Connect the laptop to an external monitor and turn it on. If you see the same corrupted, garbaged video output on the LCD screen and on the external monitor, then most likely the problem is caused by the VGA board. Before you replace the video board, try to fix the problem by reseating it. Disconnect the video board from the system board and put it back in place, make sure that it makes a good connection with the system board. If after reseating the VGA board the video problem still occurs then next step would be replacing the video board.
You can also use this guide if you want to remove and replaced memory modules, modem board, keyboard, DVD/CD-ROM drive, top cover and LCD screen assemblies.