What is causing random reboots! Dell CS doesn't know!

My laptop is rebooting on its own every now and then. I close my lid, the computer goes in to suspend... every so often when I open my lid back up to use the computer, when it tries to come back up I see the XP Pro sign on screen then after a few seconds the laptop just restarts...

I called dell once and wasn't too pleased with the knowledge and support of the heavily accented lady I spoke with (nor the LONG hold time, even with express service code). All she had me do ws go in power options and choose NEVER for 'turn off monitor' and 'turn off hard disks'. This was weeks ago and it didn't solve my problem... I use my laptop in class so settign 'when i close the lid of my computer' to DO NOTHING is not what I want to do, as I can not spare the battery life by doing that.

I got the laptop in october and have a 3 year warranty on it. I'd like to know if my laptop is defective some how and if it needs servicing. I am moving to hawaii come august and need the laptop to be in excellent working condition. I have also updated my bios to the latest as well as downgraded a step or two with no results. I'm hoping some one here has an idea what my problem could be, as I have no idea nor does dell customer support. I am trying not to call dell again if possible as  people here seem to know more than they do.

Anyone have any ideas why my computer will restart itself for seemingly no reason? Upon the last occurance a few minutes ago when windows came back up I got a popup saying THE SYSTEM HAS RECEOVERED FROM A SERIOUS ERROR. it says a log has been created. i click to view the data contained in the report but see nothing relevant.

thanks for any and all help in eliminating this problem. Do I have defective hardware?

Brian