Static from speakers while online, fixed after modem reboot

I did not know where to put this so I put it here. I started having static coming from my speakers whenever I was online and it was particularly noticeable when I was downloading a file. This happened with regular speakers or with headphones so I knew it couldn't be the speakers. Also, it only occurred when I was surfing graphic intensive websites or downloading files.

I googled everything I could find about speaker static and never found anything to indicate that the modem might be the problem. So yesterday after a storm went through and knocked out the power for about a minute the modem, of course, rebooted. After that the static I had for many days disappeared. Was wondering if any of the gurus here every heard of this and what might have caused a reboot to fix the problem.