PE Trojan,
32bit PE Trojan, dubbed W32/Aspam which was sent supposedly from Microsoft as an AntiSpam tool, is in fact a remote access trojan. Microsoft does in fact never distribute files by email.
This Trojan, in order to install itself, drops a DLL file into the Windows\system folder as "AMCIS32.DLL" and then modifies the registry in several places to load this DLL to be used with Explorer.exe, the Windows shell application. Registry changes after running the binary attachment. One gets infected by running the file ASPAM.EXE either intentionally or accidentally, which will install this trojan whereby it will run at next Windows startup.