What is it?
TROJ_ISAPASS.A - ISASS.EXE

What does it do?
It then transfers control of execution to the dropped file ISASS.EXE.

It deletes PWL files found on the system and performs key logging routines.

It runs on Windows 95, 98, NT, ME, 2000, and XP.

Also using:

• MSSVCHST.DLL
• MSHLPAPI.DLL

Removal:
Trend Micro has the full dirt ( HERE )