what is error code ME516-5W?

I have a HP Pavillion pc which is just over two years old, the above error code has come up! I have carried out a hard drive scan which showed no faults, but the memory test shut Windows down and stated a file which was missing or corrupt - windows root system32ntoskrnl.exe. Can this be fixed? I am sending this message from a different pc as I can't get our home pc to do anything. Your help is much appreciated