Possibly a scheduled task. Download Microsoft's
Autoruns, unzip the files, find "autoruns.exe". right-click it and select "Run as administrator". When the Autoruns window appears, click "Scheduled Tasks" at the top, wait until you see "Ready" in the bottom left corner, then scroll down and look for any yellow lines. If you find any, left-click on it once and see if "task.vbs" is shown at the bottom of the window. Repeat this for any yellow line. If you find one with "task.vbs", remove the check mark at the left of the line or just delete it.
Ben