BSOD during game install, can't get to desktop or startup repair

[ZenKeys88]

Yesterday I went to play a Steam game I haven't played in a few months. Since I haven't had Steam on during this time, it decided I needed to update a number of things, which included installing the 2013 version of the game. While it was doing this I got a BSOD, and now I can't get to my desktop or login screen or load startup repair.

Things I have tried:

1 - Attempt to boot in safe mode (with or without command prompt or networking) this got me past the login screen to a black abyss once, normally it gets stuck around the file ahcix64s.sys. Yes, I have read some guides on how to get around the ahcix64s.sys problem, but all of the guides I've found assume you can make it to the desktop or startup repair.

2 - Launch Startup Repair. It will not load from the computer (load bar gets completely stuck) and loading it from the install disc just tells me Startup Repair cannot fix anything because it is offline.

3 - Try things like chkdsk and sfc /scannow in command prompt when I could still load the install disc. Didn't yield any useful information, just told me I either couldn't do these checks or they were already happening and I can't get the results because things are offline.

4 - A friend installed Ubuntu on a flashdrive and we attempted to boot to the computer image on that flashdrive, but apparently with this particular motherboard you can't boot from a flashdrive.

I'm running out of ideas, best option at this point seems to be grab the hard drive from the upstairs computer, boot to that, get into my C: drive and rescue what files I can or move them to the D: drive, then reinstall Windows entirely. Hopefully SevenForums has some other suggestions for me before I have to do this.

Relevant computer information:
Windows 7 SP1 x64 Home Premium
AMD 965 Phenom II Deneb X4 3.4GHz processor
Gigabyte GA-MA790GPT-UD3H
8 GB Kingston RAM
1x Plextor DVD drive
1x HP card reader
2x WD 750GB Caviar Black drives on RAID 0 for C: drive
2x WD 1TB Caviar Black drives on RAID 1 for D: drive
NVIDIA GTX 560 graphics card, 2x LG monitors
M-Audio 192 Delta Audiophile card

**EDIT: Removed bit about being unable to access install disc, I can do so now, but I have to take Hard Disk out of the boot options entirely.

 

[Arc]

Welcome aboard.

Download Partition Wizard Bootable CD iso, and burn it using another computer you have access to. Then boot into it.

Mark the 100 MB hidden System reserved partition as active.
:ar: Follow the method three of the tutorial: http://www.sevenforums.com/tutorials/71432-partition-mark-active.html

Now, Rebuild MBR of the HDD.
:ar: How to Rebuild MBR with partition manager

Let us know the results.

 

[ZenKeys88]

I've burned the iso file to a CD, but the computer doesn't seem to recognize the CD, still have Hard Disk totally gone from the boot order. It gets past the RAID checks and so forth, then just stops.

Also tried to do a repair install, but got the "A CD/DVD device driver is missing" notice, I have three different install discs here, in previous cases one would get past this error and the others wouldn't. Now all of them don't get past this problem. At those times, the missing driver message had nothing to do with the actual problem, but perhaps it actually can't read the CD this time?

 

[ZenKeys88]

UPDATE: Made it to the desktop! Turns out my card reader was part of the problem, as it's plugged into a USB thing on the motherboard, and while it's never caused a problem before, this time it did. Anyway, I backed up most of my files, ran CCleaner and it got rid of a few things. I tried to uninstall the game entirely, but it couldn't even get started. Computer was increasingly slow, eventually crashed when I tried to open a folder of things I wanted to move. BSOD error "IRQ IS NOT LESS OR EQUAL" might have the wording a bit off.

Now I'm back to square one, can't get to the desktop, can't run safe mode, etc. etc.