Robin Hoods Playground

Hello ppl, i have a new xbox360 with a BenQ VAD6038 and a sata adapter with VT6421A chipset, i tried to flash the drive, 1st time i wasn't really clear about the procedure i was following the Textbook for noobs 2008, wasn't able do the firmware backup (it's a good tutorial but something isn't really clear there), then i was trying again after reading some stuff at the forum (i should've turn on, turn off, turn on, turn off, so it changes state), again i open the xbox and when i was about to do the thing BAM! something "explodes" somewhere (PC or Xbox), i was only thinking about my new xbox while i was closing the case again... you can imagine the feeling i think (noob playing with fire =P)... good thing it was something on the PC haven't checked yet what it is, probably PSU or Motherboard i'll check it out on my day off, i know the tutorial covers the "ground connection" issue, i didn't ignore the step i was just thinking(n00b), that it didn't seem a good idea to connect the two cases together because of the voltage that runs on the pc case, at least i think it has some. My doubt is, what really happens when you connect the two cases, how does the PC "true earth" ground works?

( Quoting the textbook "...The Xbox 360 uses a floating point ground. Your PC uses a “true earth” ground. This difference can cause excess voltage to travel through your SATA cable and potentially damage your Xbox 360 DVD drive or PC Motherboard / SATA card. Remedy this problem by connecting the Xbox 360’s ground to the PC’s ground..." )

i have hooked up the ground on some and not on others .
i dont think that not hooking up the ground would hurt the computer.
if you have not watched the video have a look.
http://www.robinhoodsplayground.com/for ... =110&t=277" onclick="window.open(this.href);return false;