This is bad for me, but it's worse for people who enter sweepstakes at work, especially if they don't have the option of turning down their computer speakers (which is how I usually handle it).
To help solve this problem, I've created a new article, How to Turn Off Sounds in Your Internet Browser. This is a quick and easy guide to turning off those annoying boos, cheers, clacks, bangs, and whatever other noises that websites like to spring on you, while still letting you listen to music through iTunes or a music player. It should work for any internet browser on any computer running the Windows operating system.
I do sometimes like to listen to sound through my browser (for instance, if I'm watching a movie trailer), so I plan to use this method to turn off sounds while I'm entering sweepstakes, and turn them back on again afterwards. Let me know if this works for you.
More Technical Assistance for Sweepstakes Entry