On a Dell E4300 laptop what does the button to the left of the power button do?

It is the "Latitude On" button, which is supposed to give you a much quicker start, and much much longer battery life (with many of your same apps) by not loading Vista, but rather loading a version of Linux which is hard coded on your chip. http://en.wikipedia.org/wiki/Latitude_ON Early versions of E4300's (like mine) only have it in a "reader" mode, but upgrades are on their way It seems like an attempt to get the best of both worlds ... the low-power perks driven by UMPCs, and the high power features common on Vista machines. Great idea! by the mobile learning team at www.m-learning.org