|Note that in all downloads uncheck any unwanted toolbars or programs they offer as part of the install.|
First download, install and run CCleaner from here:
In Settings ensure you have a check mark in all temporary file entries (Windows and Applications).
Download install and run MalwareBytes from here:
Finally run your normal AV scans.
Never heard of RUN.DLL so please recheck the exact error message.
Always pop back and let us know the outcome - thanks