Windows crashes automatically if you don't switch off the machine for 49.7 days.This is accepted by Microsoft. Do you know why? In windows the Virtual Machine Manager(VMM) is responsible for creation, execution, monitoring and termination of virtual machines. This VMM is a 32 bit protected mode operating system, provides a number of system service at chip level of programming. One of these services is "Get_System_Time". This particular service loads the EAX register with the time in milliseconds since Windows started.This service is accurate to 1ms. EAX is a 32 bit register. So the maximum number of milliseconds it can hold is: (2^32) - 1 = 4294967295 milliseconds = 4294967.295 seconds = 71582.79 minutes = 1193 hours = 49.7 days So after 49.7 days the EAX resets to zero.Most of the Drivers use this Time Service to keep track of the time out of various services they provide. So after 49.7 days the drives cannot use the Get_System_Time funtion of VMM and they crash.