Started PC, BSOD.

A problem has been detected and windows has been shut down to prevent damage to your computer.

IRQL_NOT_LESS_OR_EQUAL

If this is the first time you've seen this Stop error screen, restart your computer. If this screen appears again, follow these steps:

Check to make sure any new hardware or software is properly installed.
If this is a new installation, ask your hardware or software manufacturer for any windows updates you might need.
If problems continue, disable or remove any newly installed hardware or software. Disable BIOS memory options such as caching or shadowing.
If you need to use Safe Mode to remove or disable components, restart your compute, press F8 to select Advanced Startup Options, and then select Safe Mode.

Technical Information:

*** STOP: 0x0000000A (0xE3181183,0x00000002,0x00000000,0x8A93AB24)

Can you post the dump files by following the Blue Screen of Death (BSOD) Posting Instructions

It might take a while, the BSoD keeps looping almost everytime I try to start my PC.

Try booting into safe mode. Press F8 on startup and choose Safe Mode with networking.

There you go.

Right, for a start your graphics driver is a bit outdated. Please update it following these instructions.

support.amd.com/en-us/kb-articles/Pages/catalyst-windows-install.aspx

Code:

9443e000 94e29000   atikmdag T (no symbols)           
    Loaded symbol image file: atikmdag.sys
    Image path: atikmdag.sys
    Image name: atikmdag.sys
    Timestamp:        Tue Apr 30 03:02:54 2013 (517F264E)
    CheckSum:         009A2A46
    ImageSize:        009EB000
    Translations:     0000.04b0 0000.04e4 0409.04b0 0409.04e4

You appear to have memory corruption which is most likely caused by bad RAM, even though you can boot in safe mode it's better to be safe than sorry.
Follow these instructions on how to run memtest86

RAM - Test with Memtest86+

Code:

*******************************************************************************
*                                                                             *
*                        Bugcheck Analysis                                    *
*                                                                             *
*******************************************************************************

Use !analyze -v to get detailed debugging information.

BugCheck 1000007E, {c0000005, 9477b24b, 80e5647c, 80e56060}

Probably caused by : memory_corruption

Followup: memory_corruption

Apart from this there isn't much else that helps. Can you enable Driver Verifier by following these instructions.
When you choose the drivers DON'T enable any drivers from Microsoft Cooperation, Unknown or Macrovision.

When I try to update my graphics driver or to install "Auto-installer for USB Key (Win 9x/2k/xp/7)" I get the "NSIS error".

Try running your Anti virus as viruses can cause these issues.
Can you also run a disk check by following these instructions.

Disk Check

Called someone to come and repair it, thanks for the help tho.