When I first set up BOINC on my new Win 7 rig (a few months back,) exactly the same thing happened to me. At the time, I just assumed that the icons had appeared (then just got left behind,) marking the times I'd opened the new installation to see that it was functioning correctly....)
Anyway, I manually closed the
extra icons, leaving just one of them behind. It happened a couple of times more, but I repeated my closure of the "extras" and it just seemed to settle down after that. (I know this is not in any way a "technical" reply, but hey, it worked for me, lol.)