Had this same behaviour in an iOpener I was hacking a couple of years ago. Turns out it was picking up ir commands from a remote my son was using for one of his toys. It sent out signals on the same bandwidth whether he was using it or not. Almost like it was polling or something.
Are there any other ir sources near your computer when you reboot? Try covering the ir port and rebooting. I had to disconnect my ir keyboard and reconnect a standard keyboard to make this stop.
Hope this helps.