Chris Pirillo posted two remixes of the famous Windows XP startup sound, the one you hear every time you turn on your computer (until you get sick of it and shut it off).
This one is my favorite, a really nice piano tune:
The other one is not as good, but has more pop to it:
There are a ton of other Windows sound remixes on YouTube, like this one, which use a bunch of different system sounds:
This one might do it even better: