Rundll32.exe is a Microsoft application and is not harmful for your PC. Rundll32.exe process is just like a host and open Dynamic link libraries (.dll) files even if they are not executable by own. Rundll32.exe performs the same functionality as svchost.exe. Only the difference is, rundll32.exe controls .dll files of third party and svchost manage .dll files of internal system.
Rundll32.exe is not a virus but problem arise when any malicious program come in to the system and make use of files having name with the extension “.exe”. Most Windows install rundll32.exe file in “C:\Windows\System32\rundll32.exe” or “C:\Windows\SysWOW64\rundll32.exe”.
To make deeper investigation, install “Process Explorer” program about rundll32.exe. This program gives you list of .exe files which are currently running on your computer. Mouse hover on any file and you will get all details and description of that process. You can check what rundll32.exe file is currently doing from “Process Explorer” program.
