Hello... please tell us the following:
1. Your PC configuration ( Motherboard, CPU, RAM, Hard Disk, Power Supply, etc ).
2. How old is it?
Meanwhile, check the following:
1. Does all the fan in your PC spins? If not, it may be causing some overheating in some of your components that cause your PC to freeze.
2. Did you installed any new component or application recently that might have triggered this random freezing?