there might be the problem with the power which is provided to the HDD by the laptop. so it seems that it is damaging the HDD that's why your laptop is failing the boot process. and the other thing might be there is RAM. try to replace your RAM and see if it works or not.
you should check the connected cables with the WiFi adapter chip if you have opened your laptop. if all the connections seems ok then you should try universal driver pack solution it will install the missing drivers that may very from its original vendor but it might help.
if any of these don't...
you will find complete guide to repair your laptop on youtube.....
and dont try to use your energy if any of the part dosent comes out check the bolts and locks otherwise you will break your laptop......
http://www.newegg.com/Product/Product.aspx?Item=N82E16834317427
thil will be best for your kid according to me ....
this laptop can be used ruff also which children usually do....
install the proper driver for your camera.
if you are using the sdcard then try to find them in hidden files.
it may possible that your machine is having virus which is causing the problem....