The most typical cause for a system lockup is which of the following?

a. Old operating system
b. Incompatible app
c. Slow hard disk
d. Memory corruption

D System lockups are typically caused by the corruption of memory contents. Consider the following to rectify:
Step 1: Shut down the system, remove and reinstall memory, and remove dust from the modules, the sockets, cooling vents, and fans. If the problem persists, memory might be overheating.
Step 2: Check the specifications for memory; the memory installed might not be the correct type for the motherboard and processor. If memory is incorrect for CPU or motherboard, replace it with correct-specification memory.
Step 3: If memory has been overclocked, reset the memory to factory specifications by using the Auto or SPD options in the system BIOS setup.
Step 4: Add additional system cooling.