BAD_POOL_CALLER is related to memory problems. Most of the time when I have encountered Blue Screens, even though it is supposed to be a software issue, it is due to problem with memory modules. Due what you said you're trying to do, which is put a load on the system, I think one or more of your memory modules is on the verge of complete failure. I recommend you run Memtest 86 as Physics suggested. If you don't want to do that, then do this:
(1.) Power off the system and unplug from the wall, you don't have to disconnect anything else.
(2.) Hold the main power button in for 10 seconds to discharge the system's capacitors.
(3.) Open up your case and locate your memory modules, you have a maximum of 2.
(4.) If you have only 1 module, stop right here, unless you have a spare DDR2 module you can use you are stuck. You will have to remove the 1 module and replace it with the spare.
(5.) If you have 2, then remove the 1 furthest from the processor.
(6.) Close the system back up, plug it back in, power it up and do whatever you were doing before. If you have problems then that module is bad.
(7.) If nothing goes wrong, then repeat #1, through #3 and swap modules, and repeat #6.
(8.) If nothing goes wrong then it's most likely a software problem.
(9.) Repeat #1, through #3 and reinstall both modules.
(10.) At this point post back, and we'll work the problem further.
In case you don't have the manual handy, here's a link:
http://support.dell.com/support/edocs/systems/dim3100/en/sm/index.htm
