LATITUDE E5500 crashes when connected on lan via network cable

I have a Latitude E5500 and it's brand new. I've installed on it VS 2005, SQLServer 2005, XP Mode which communicates with the host (WIN7) thru Microsoft Loopback adapter, and bunch of other stuff.

But even before all of that when I connected it on network (at home or at office) it would crash at some point in work-time. The light for hard disk goes blue all the time and the hard disk sound like it is jammed, similarly to CDs when they cannot be read. System then goes down, BSOD shows for a blink of an eye and it restarts. After it restarts there's only message that system cannot find the system drive, like my hard drive is dead or something.

What I do i is to shut it down on power button and start again. It starts normally with only Q for starting Windows normal, safe mode etc. I start it in normal mode and all goes smoothly.

I've run all diagnostic I could think of: HDD diagnostics, system diagnostics, even DELL diagnostics (FULL) and everything shows no errors. I've reinstalled the LAN driver for my network card (BROADCOM NetXtreme 57xx Gigabit Controller) but it doesn't solve the problem.

I thought it might have something to do with Microsoft Loopback Adapter so I've disabled it and it still crashes.

I'm already desperate so any help would be more then appreciated.

P.S. I'm sorry if I've made errors in writing, English is not my first language after all :D. Cheers!!!