To decrypt your files, the first thing that you should do is terminate the firefox.exe and drpbx.exe processes in Task Manager to prevent any further files from being deleted. You should then run MSConfig and disable the startup entry called firefox.exe that points to the %UserProfile%\AppData\Roaming\Frfx\firefox.exe executable.
Then run the decrypter. Choose a directory and select "Decrypt My Files".
After it's finished, it will say "Files Decrypted". After it appears, you may close the program as your files have successfully been decrypted. It's best to then fun a full anti-virus scan to clean out any leftover and unwanted files.
If you have any questions or concerns, please don't hesitate to contact one of our Security Staff members.