That widget gets its information from a cookie stored on your computer. If you delete your cookies, you delete the info needed to show your countdown. Sometimes, a computer is set to automatically remove your cookies - for security reasons. So, you may need to go in and adjust your settings. My countdown is at 16 days!!!
I just don't like that they automatically start when I turn on my computer. I have to X out of them otherwise they hog my screen. Wish they could be minimized as well.
I've noticed that it is a memory hog as well. 26MB of RAM for a widget seems a bit excessive to me. I let it start, and then turn it off for now. Our vacation isn't until next summer, so will wait til we get closer to leave it up.
I ahve to continuously reset mine too, more of a pain. I know my cookies don't delete every time I turn my computer off so it has to be something else.