Follow the steps:
1- Restart your computer in safe mood
2- Search the files with the extention '.eml' Click start and then click at search type .eml only in the search box and select all drives for it then search and delete all the files.
3- Type regedit in RUN and then OK.Press Ctrl + F and type runouse then find it and delete all the entries which showed up.
Get Bitdefender antivirus or any other paid antivirus for keeping your system safe.