When I switch on my computer it freezes on the memory check. It checks the processor, that is OK. It starts to check the RAM, then it freezes. It will not respond to any command and will not switch off. I have put the memory in a different computer and it works fine. I have put it in different slots and singly, but makes no difference. Can anybody help, or is the problem terminal. I have had the computer for three years with no problems and did not change anything before the fault occured.