For whatevaer reason, my laptop went crazy, it prompts “SupportAssist” and it has gone through rounds of “fixing”, failed in the end.
Luckily, at some step, it prompts to back up all data and luckily I am able to backup all data. Pretty scary loosing all the data.
But, it can’t fix itself by reinstall Windows Professional 64-bit. It seems that it has lost the partition on the hard disk. Therefore, I am on my own now.
I went to Dell and found some way to survive.