Hi Conrad,
Rundll32.exe is a program used to run program code in DLL files which is part of Windows components. There are viruses that uses this name also that's why it's commonly mistaken as a real virus. There are also times that the file gets replaced with a malware infected one. I suggest that you use the System File Checker tool to scan your system files and to repair missing or corrupted system files. The sfc/scannow command (System File Check) scans the integrity of all protected operating system files and replaces incorrect, corrupted, changed or damaged versions with the correct versions possible. You may refer to this linkfor more information.
I will wait for your response.
Regards.