Your specs still say Studio MT, if you could update that please it would be appreciated. We do rely heavily on those specs and it really does help us help you.

Onto the drivers. The faulting USB3.0 drivers have been flagged in the dumps, two of them to be exact. The first one blamed is the Intel eXtensible Host Controller, then the Intel USB3.0 Hub driver.
Code:
*** WARNING: Unable to verify timestamp for iusb3xhc.sys
*** ERROR: Module load completed but symbols could not be loaded for iusb3xhc.sys

Use !analyze -v to get detailed debugging information.

BugCheck 1000007E, {ffffffffc0000005, fffff8800504e3b4, fffff8801296d4d8, fffff8801296cd30}

Probably caused by : iusb3xhc.sys ( iusb3xhc+4e3b4 )

0: kd> lmvm iusb3xhc
start             end                 module name
fffff880`05000000 fffff880`050c8000   iusb3xhc T (no symbols)           
    Loaded symbol image file: iusb3xhc.sys
    Image path: \SystemRoot\system32\DRIVERS\iusb3xhc.sys
    Image name: iusb3xhc.sys
    Timestamp:        Mon Mar 30 17:03:48 2015 (551973E4)
    CheckSum:         000C8429
    ImageSize:        000C8000
    Translations:     0000.04b0 0000.04e4 0409.04b0 0409.04e4
Code:
fffff880`1296cc08  fffff880`05828000Unable to load image \SystemRoot\system32\DRIVERS\iusb3hub.sys, Win32 error 0n2
*** WARNING: Unable to verify timestamp for iusb3hub.sys
*** ERROR: Module load completed but symbols could not be loaded for iusb3hub.sys
 iusb3hub

0: kd> lmvm iusb3hub
start             end                 module name
fffff880`05828000 fffff880`0588b000   iusb3hub T (no symbols)           
    Loaded symbol image file: iusb3hub.sys
    Image path: \SystemRoot\system32\DRIVERS\iusb3hub.sys
    Image name: iusb3hub.sys
    Timestamp:        Thu Oct 30 10:05:14 2014 (54520D5A)
    CheckSum:         00066231
    ImageSize:        00063000
    Translations:     0000.04b0 0000.04e4 0409.04b0 0409.04e4
If you look at the dates the XHCI driver is newer than the Hub driver, whether that's causing the problem I don't know. I've checked the Dell website support page and I can't find anything newer than either of them for that model PC. I'll have to have a look around the Intel site and see if anything shows up.

One other driver of note is the ATI driver.
Code:
fffff880`1296ca88  fffff880`0f2f58bbUnable to load image \SystemRoot\system32\DRIVERS\atikmdag.sys, Win32 error 0n2
*** WARNING: Unable to verify timestamp for atikmdag.sys
*** ERROR: Module load completed but symbols could not be loaded for atikmdag.sys
 atikmdag+0x818bb

0: kd> lmvm atikmdag
start             end                 module name
fffff880`0f274000 fffff880`0febb000   atikmdag T (no symbols)           
    Loaded symbol image file: atikmdag.sys
    Image path: \SystemRoot\system32\DRIVERS\atikmdag.sys
    Image name: atikmdag.sys
    Timestamp:        Sat Aug 31 01:02:50 2013 (522132AA)
    CheckSum:         00BF596C
    ImageSize:        00C47000
    Translations:     0000.04b0 0000.04e4 0409.04b0 0409.04e4
This one's pretty old and needs updating. Download the latest driver for your card from here and save it to your desktop. Download DDU and follow Display Driver Uninstaller: How to use to remove all traces of your current driver. Reboot and install the downloaded driver.