All my files have been encrypted with locky virus: I tried CCleaner, M.S. Forefront, and some other antimalware programs;
Can anyone give me some advice about this virus removal?
If they've really been encrypted, you personally can't do anything to recover the encrypted data.
For the future, make frequent backups, and consider using Linux (or a VM) if you must visit shady websites and/or run unknown software often.
It depends on the virus. There are many viruses that just claim something that is not fully true. There are 3 major possibilities:
The first option is the most scary but it is the most difficult to implement. Restoring of the data from creators is difficult for them. So this is not the most common option.
A nice plan for you is: