samsung galaxy s2 continually flashes and will not turn on
As far as I can tell this is what you need to do. NOTE: This information comes from my research and not my experience and while this may make your phone usable you may lose your data. I suggest removing your microSD card as it is most likely where your pictures and video are:


Download ODIN from here
Register at Sammobile here
Download your firmware here
Open ODIN
Put your Firmware.tar file in the PDA box and tick PDA (DO NOT TICK OR UNTICK ANYTHING ELSE)
Attach your phone to your computer using your USB cable and click Start. Don't do anything else until it is done.