Kernel Panic Error on boot up

Question

Hello everyone,
I hope someone can help me with this....
Everytime I boot my Macbook Pro (2012, 15inch Retina version) it gets stuck in a boot- kernel panic error-reboot loop. Ive mananged to boot into it (see below) to take a look at the logs, I have attached the log to the bottom of this post.
I have windows installed on this computer too, so I tried booting into it and I seem to get the same situation - windows reboots after what I can only assume to be a kernal panic.
Now interestingly if I hold down shift during the boot onosx (NOT booting into safe mode, after the spinning icon is already showing) I can boot up - I am not sure why though? I assume I am disabling some kernal extensions?
Things I have done:
Run the mac hardware test 3 times, no errrors reported
Run disc checking/verifying 3 times, no problems reported
Checked kext to see if there are any non official extensions, none all are com.apple.* or NVIDA stuff
Reset NVRAM and SMC controller
I am not really a mac expert but looking at that log it looks graphics card related? To test this - I downloaded gfxCardStatus and forced it to use the discrete graphics card and it seems to be using it with no problems. I the forced only the on board card to check if that was ok and it was.
So where should I go from here? If it was a hardware failure it would be happening every time and I wouldnt be able to use the shift key to boot up right?
If it was only software, why would it be happening to windows too?
Help me please!
Anyway, thanks for reading this.
panic(cpu 0 caller 0xffffff80088b7b95): Kernel trap at 0xffffff7f89c00654, type 14=page fault, registers:
CR0: 0x0000000080010033, CR2: 0x0000000000000010, CR3: 0x00000000185e302f, CR4: 0x00000000001606e0
RAX: 0x0000000000000001, RBX: 0xffffff80db953000, RCX: 0xffffff801e4b9550, RDX: 0xffffff80fcd0ba38
RSP: 0xffffff80fcd0bb60, RBP: 0xffffff80fcd0bb60, RSI: 0x0000000000000000, RDI: 0x0000000000000000
R8:  0x0000000000000000, R9:  0x00000000000003ff, R10: 0xffffffffffffffff, R11: 0x00000000ffffffff
R12: 0xffffff80db953000, R13: 0x0000000000000000, R14: 0x0000000000000002, R15: 0x0000000000000000
RFL: 0x0000000000010246, RIP: 0xffffff7f89c00654, CS:  0x0000000000000008, SS:  0x0000000000000010
Fault CR2: 0x0000000000000010, Error code: 0x0000000000000000, Fault CPU: 0x0
Backtrace (CPU 0), Frame : Return Address
0xffffff80fcd0b800 : 0xffffff800881d5f6
0xffffff80fcd0b870 : 0xffffff80088b7b95
0xffffff80fcd0ba40 : 0xffffff80088ce4ad
0xffffff80fcd0ba60 : 0xffffff7f89c00654
0xffffff80fcd0bb60 : 0xffffff7f89bea18c
0xffffff80fcd0bbb0 : 0xffffff7f89bea0e2
0xffffff80fcd0bbd0 : 0xffffff7f89bbb554
0xffffff80fcd0bc00 : 0xffffff7f89435470
0xffffff80fcd0bc40 : 0xffffff7f894353df
0xffffff80fcd0bc60 : 0xffffff7f8943a6ec
0xffffff80fcd0bcf0 : 0xffffff7f89432f20
0xffffff80fcd0bd20 : 0xffffff7f89502cc7
0xffffff80fcd0bd70 : 0xffffff8008c33b9b
0xffffff80fcd0bdc0 : 0xffffff8008c62d57
0xffffff80fcd0be30 : 0xffffff8008897cef
0xffffff80fcd0be80 : 0xffffff8008820abd
0xffffff80fcd0beb0 : 0xffffff8008810448
0xffffff80fcd0bf00 : 0xffffff80088195fb
0xffffff80fcd0bf70 : 0xffffff80088a5ad6
0xffffff80fcd0bfb0 : 0xffffff80088ced13
      Kernel Extensions in backtrace:
         com.apple.iokit.IOGraphicsFamily(2.3.4)[5D671681-D21B-3CCA-9810-B15E648C1B27]@0 xffffff7f89429000->0xffffff7f8945ffff
            dependency: com.apple.iokit.IOPCIFamily(2.7)[8C9E06A4-13D0-33F5-A377-9E36F0ECC229]@0xffffff 7f88d86000
         com.apple.NVDAResman(8.0)[6A699209-FB98-316B-A3C0-DCA82AA8C86B]@0xffffff7f89500 000->0xffffff7f89802fff
            dependency: com.apple.iokit.IOPCIFamily(2.7)[8C9E06A4-13D0-33F5-A377-9E36F0ECC229]@0xffffff 7f88d86000
            dependency: com.apple.iokit.IONDRVSupport(2.3.4)[E37F420A-B5CD-38ED-9441-5247583B6ACE]@0xff ffff7f894c5000
            dependency: com.apple.iokit.IOGraphicsFamily(2.3.4)[5D671681-D21B-3CCA-9810-B15E648C1B27]@0 xffffff7f89429000
         com.apple.GeForce(8.0)[91C40470-82BA-329A-A9D7-4C70F28275FD]@0xffffff7f89bba000 ->0xffffff7f89c7cfff
            dependency: com.apple.NVDAResman(8.0.0)[6A699209-FB98-316B-A3C0-DCA82AA8C86B]@0xffffff7f895 00000
            dependency: com.apple.iokit.IONDRVSupport(2.3.4)[E37F420A-B5CD-38ED-9441-5247583B6ACE]@0xff ffff7f894c5000
            dependency: com.apple.iokit.IOPCIFamily(2.7)[8C9E06A4-13D0-33F5-A377-9E36F0ECC229]@0xffffff 7f88d86000
            dependency: com.apple.iokit.IOGraphicsFamily(2.3.4)[5D671681-D21B-3CCA-9810-B15E648C1B27]@0 xffffff7f89429000
BSD process name corresponding to current thread: WindowServer

Answer 1

Please read this whole message before doing anything.
This procedure is a diagnostic test. It’s unlikely to solve your problem. Don’t be disappointed when you find that nothing has changed after you complete it.
The purpose of the test is to determine whether the problem is caused by third-party software that loads automatically at startup or login, or by a peripheral device. 
Disconnect all wired peripherals except those needed for the test, and remove all aftermarket expansion cards. Boot in safe mode* and log in to the account with the problem. The instructions provided by Apple are as follows:
Shut down your computer, wait 30 seconds, and then hold down the shift key while pressing the power button.
When you see the gray Apple logo, release the shift key.
If you are prompted to log in, type your password, and then hold down the shift key again as you click  Log in.
*Note: If FileVault is enabled under OS X 10.7 or later, or if a firmware password is set, or if the boot volume is a software RAID, you can’t boot in safe mode. Safe mode is much slower to boot and run than normal, and some things won’t work at all, including wireless networking on certain Macs. The next normal boot may also be somewhat slow.
The login screen appears even if you usually log in automatically. You must know your login password in order to log in. If you’ve forgotten the password, you will need to reset it before you begin. Test while in safe mode. Same problem? After testing, reboot as usual (i.e., not in safe mode) and verify that you still have the problem. Post the results of the test.