The blue screen of death is nothing good. What version of Windows are you running? Have you installed any programs? Have you un-installed any programs? If you have installed or un-installed, system restore will most times correct the problem. If I was you, I would back up all works, photos, etc and do a complete re-install as mentioned by methyl. In doing this, it will format your hard drive, rewrite all root and boot sectors and if there are cross files/paths this will fix the problem that caused the errors. Most times the blue screen is when two different programs running in the background or one running in the background and one you are using; try to access the same block of memory. They collide, bouncing back/returning with an invalided answer or command, thus the blue screen comes up, and most times the only thing you can do is hard shut down/restart. Removing the battery and unplugging, this is not good and doing it to many times it will definitely case your system to totally crash the operating software. All answers given are correct and accurate; however, we all need more info from you.