Nail.exe is a part of the new generation of VX2 adware components. Nail.exe is protected from deleteion by Delprot driver. Delprot.sys is the driver used to protect adware registry keys from deletion. Also related files: %WinDir%\isrvs\ffisearch.exe %WinDir%\isrvs\desktop.exe %SysDir%\Drivers\delprot.sys
Removal: Go to the Safe mode. Delete the key HKLM\SYSTEM\CurrentControlSet\Services\Delprot Remove ffisearch.exe and desktop.exe from Windows startup registry keys using antivirus (also check How To Remove section) Delete Files: %WinDir%\isrvs\ffisearch.exe %WinDir%\isrvs\desktop.exe %SysDir%\Drivers\delprot.sys
Kill the process %WinDir%\Nail.exe and remove %WinDir%\Nail.exe from Windows startup.