I have an issue with my computer?

well, for whatever reason, when i double click on an icon, i asks me what i'd like to open it with. that was starnge, so i right clicked and saw it say that the first option and the double click option was OPEN on a executable file. is this normal? if it is than am i missing the "program" to open them with. im perplexed because they work if i right click and push start as admin. it happend after i ran norton anti virus, so i cant help but think something happend.