What is rundll32.exe ?
 

If you've been around Windows for any amount of time, you've seen the zillions of *.dll (Dynamic Link Library) files in every application folder, which are used to store common pieces of application logic that can be accessed from multiple applications.

Since there's no way to directly launch a DLL file, the rundll32.exe application is simply used to launch functionality stored in shared .dll files. This executable is a valid part of Windows, and normally shouldn't be a threat.

Note: the valid process is normally located at \Windows\System32\rundll32.exe, but sometimes spyware uses the same filename and runs from a different directory in order to disguise itself. If you think you have a problem, you should always run a scan to be sure, but we can verify exactly what is going on… so keep reading.

http://www.howtogeek.com/howto/windo...is-it-running/