Help me, Keylogger

[archery]

Greetings to all forums, my friend asked me for help because Avast found in his PC a KeyLogger:
Win32: NT-KeyLogger on a DLL system32 msiunaerpm.dll and after that Avast indicates continually attack blocked: LSASSEXPLOIT ATTACK (SXP).
I must help you tonight, I think Avast remove and install NOD 32 2.5.32 But I would like to know your opinion before you start doing anything.

I know that I have little information from you, but that's all I know also I

[archery]

Nobody can help me?