In Microsoft Windows platforms, a blue screen on a user's monitor indicates that something has gone seriously wrong with the system.
In Windows 2000, this screen is usually called a Stop screen, and it contains complex information that qualified support technicians can use to diagnose the problem.
A reboot might get the system going again, but the blue screen might reappear if the problem is not resolved. The problem causing the blue screen to appear can be either hardware-related or software-related, but the blue screen itself is generated by the operating system in response to the underlying problem.
In Windows 95 and Windows 98, the blue-colored screen normally appears when parity errors or memory violations occur. The Windows 98 blue screen requests that you either shut down the offending application or restart your system using Ctrl+Alt+Delete.
Parity errors can indicate that your system RAM has mismatched single inline memory modules (SIMMs) on your motherboard—for example, RAM with different speeds or a mix of parity and nonparity RAM. Also, systems from some manufacturers require special proprietary RAM in order to function. You should consult the documentation from your computer’s manufacturer or your RAM’s manufacturer to ensure that you have the correct type of RAM in each slot.