My toshiba satellite L655-S5146 decided to give me a black screen one day with white writing. I selected launch start up repair and it just rebooted to the same screen. Once in a while it would load my log in page and open my files but selected to restart itself giving me a blue screen. After some time of me trying the numerous trouble shooting techniques including bios reset it now won't even turn on. I plug it in hit the power button and can hear the fan the computer makes a tick sound and shuts off after 3 seconds and turns on again if I don't remove the power cord it repeats the start and off cycle.
You could try to stop the cycle by stopping the reboot on system failure. You dont mention the version of Windows, but i'll guess its 7 or before ... To do the job you need hit the [F8] key repeatedly after you switch on. Contilue to do this until the Advanced Boot Menu appears. With the arrow keys select Disable Automatic Restart On System Failure and hit [ENTER]. Hopefully you will get a blue screen with white writing on with a stop code. Let me know the code and I will try to help from there.
Also if we cant get it going again, there might be a way of retrieving your data, but it depends on the damage caused so far.
Good luck - dont forget to post back with the stop code.