Freeze Lockups XPS L701X

I have had this laptop for 2 months now and have been on tech online chat multiple times, tech phone and have had a tech to my house twice to replace hardware.

I have lockups where the mouse won't move, video is locked up but I can hear any audio playing in the background and I have to hard reboot the system daily. This occurs when I am just browsing the internet, playing a game online, basically doing anything. So there is no consistent reasoning behind the lockups I have noticed.

I have set back to original factory settings twice since recieving laptop, Windows 7 is up to date, updated BIOS, updated Graphics card driver, 2 new motherboards, new ram, new heat sink, multiple calls to tech support. Have ran all the Dell diagnostics on the hardware multiple times by myself and with tech support. Still having an issue with lockups. Is there a log somewhere I can search for on my computer that shows the error when lockups occur. Only thing I can find is under the event viewer it says critical error the system rebooted unexpectantly. This only tells me that I had to power down the computer to clear the lockup. Not the reason why or atleast a direction I can look to see why.

I need to find out what is causing the issue and maybe then I can fix it myself. The most recent call to the tech support line they suggested I send it in for observation. Which means 3 weeks of no laptop and chances are they will just reset to factory and say fixed.

Any help would be appreciated.