Something is causing it to run at start up time so press you Windows key and R together then into the Open box,m type msconfig and press Enter.
A form will come up with several tabs and you need to click on the StartUp tab. Find whatever is in the list that refers to a file in the C;\ drive - it probably won't have a programme associated with it. Remove the tick from that item, click Apply and OK your way out. Restart the machine and when it comes back up, tick "Don't show this message again" and press Enter.
If that doesn't fix things, post back because you may have a malware issue.