There is no risk involved, as long as you have your power cable connected and nothing interferes with the installation there is nothing that can go wrong.
The only thing you have to make sure, as it has caused a problem in the past, is that if your BIOS version is A02 and you update to the newest A08, it might not be able to handle it. So the suggested way to do it is to upgrade each BIOS at a time. For example, if you have A02, update to A03, then to A04 and so on.
Here is a link to the Older Versions of the BIOS for your computer: http://support.dell....eckFormat=false
That way you can download them, and make sure you click Save As, rather than Run.
Now it is a good idea to update the BIOS as it can improve system performance and battery life as well. It also addresses any known issues in the BIOS which can cause problems down the road, therefor it is a highly suggested download.
EDIT: To find out your current BIOS version, you can spot it when you restart your computer, it should say in one of the corners A05 or A07 or whatever. A08 is the newest version out
Edited by Log2, 08 February 2011 - 01:27 PM.