rundll32 - rundll32.exe
rundll32.exe (rundll32 stands for Run a DLL as a 32-bit application) is a Windows NT/2000/XP generic process used for loading dynamic link libraries (DLLs) in memory so that other programs can use them.
The file that corresponds to this process is normally found in the directory "%SystemRoot%\system32\rundll32.exe" (where %systemroot% is usually C:\WINDOWS by default).
The process rundll32 is not in any way a virus, a worm, a Trojan horse, spyware, or adware.
It is a critical system process which may not be terminated.