Look at this discussion with HP -> http://forums.cnet.com/5208-7587_102-0.html?forumID=69&threadID=271360&messageID=2699006#2699006
There were no less than 10 drivers to be found. Your machine is likely no worse or better. I can't count how many times it's a missed or incorrect driver. Only Dell may know the install routine.
I have a Dell Inspiron 1721 that came pre-installed with vista home 32. Well I hate vista and went a head and installed XP pro, after searching for days for all the driver i was able to find them. Here is where i run into issue. My power setting are Always on, Do nothing when closing lid, ect. When I run any media player weather its windows media player or AVS the power setting change. It used to be that it would throttle the CPU down, untill I found the correct chipset driver.
Anyone have ideas?