Thanks you guys a lot.
Well, I know it is only a beta and fortunately I always back-up my files when I install new stuff.
I had re-installed my windows and never run CCleaner again.
Well, I suppose there should have lots of people having the same problem.
I am not blaming CCleaner, I have already taken my own risk. I just want to find the solution.
If everyone is only allowed to install programmes that claim to support Windows 7, I cannot imagine who will still use it. (You can't even use Windows live, Office..., well same as live in a house without an article of funiture)
I did report this issue to Microsoft too.
I really hope that I can use the CCleaner again. I MISS YOU SO MUCH...