The Blue Screen of Death (BSoD for Blue Screen of Death) is the nickname for the error message displayed on a computer screen by the Microsoft Windows operating system when it cannot recover from a system error or when it reaches a critical point of a fatal error. (Wikipedia)
A blue screen appearing on a Windows computer indicates a problem on your computer, the origin of which can be various:
A problem with drivers, infection on the system, hardware problem, etc. (Read more)