When you ran norton did it find anything?
Norton likely would have found a trojan if there was one. If you want to be extra sure I would suggest you run this free tool that can find things that norton will sometimes miss.
Download the following program https://www.malwarebytes.org/trial/ (you do not need to buy it, just install and run a full scan. If it finds anything have it remove it for you. This is the trial version but works just as good as the paid version so no need to buy anything.
Please do me a favor and take a moment to rate my service by clicking the stars above, 3 or more is very appreciated, we can still chat after rating if you need more help.