So – I decided that i wanted to install Windows 7 ultimate on my beautiful new 27″ iMac – partly because Windows runs great on Apple hardware, and partly because I know that somewhere out there, there is an Apple die hard that just choked reading this ;).  If you’ve read my blog before – you’ve seen some pretty crazy configurations (My Mac Pro, for example, is a 4 O/S beast that runs beautifully – and I did everything gracefully, and without any of the bullcrap that the so called “Mac Geniuses” say you will run into….  Macs wont run 64-bit this, you have to update EFI tables that….  it’s all horseshit (pardon my french).  Macs are pretty much plain vanilla PC’s when it comes to their innards – and with a little greasing, things usually install nicely – if you know what you are doing.  Unfortunately, it seems that most people who use Macs – including the majority of the “geniuses” at the apple stores, and the “top posters” on the apple forums, blindly lead people down un-necessarily difficult paths because they simply don’t know what they’re doing.

Enter my blog….  I’ve already given you a path to create your own quad booting Mac Pro behemoth…..  and now I’ll do the same for the new iMac.  Let’s install Windows 7.  I’m not going step by step – I will assume that you have seen boot camp before and I will just cover the issues you will run into because a) I like quick, concise blog posts and b) it should still give you the information you need to be successful.

So, anyways, much to my dismay, I start by using the Boot Camp utility to partition off a 300GB Windows partition, and let it reboot into the Windows Installer.  I go through the W7 intro screens and pick the new installation pathway through the installer.  The first thing I notice is that W7 says that it cannot install on the boot camp partition because it’s not formatted NTFS.  No biggie, click the boot camp drive, click advanced, and then click format.  Presto!  the error goes away so I happily click next and start the install process.

The copy process took about 15-20 minutes it seemed – but I was not watching the clock so I might be a little off there, but it didn’t seem to take very long.  Before you know it – you will see a message saying that your computer will reboot, or, if you’re not paying attention – you’ll be blown out of your chair by the apple startup sound which, thanks to an excellent speaker setup in the new 27″ iMac, is more annoying than ever (might I suggest you click here if you find the sound annoying too?).  Once the computer restarts, you’ll see the installer load back up, finish adding a few more drivers here and there, and copy some more files, and then it will reboot again.

Uh-Oh…. here is where the trouble starts.  When you reboot – you’ll see the “Starting Windows” screen with the interesting new microsoft animation, and then your screen goes blank.  What?  What happened?  Do i wait.  Well – you can, but let me tell you – I was doing some other things so I just let the iMac sit – and 45 minutes later, the screen was still blank… so… something is “effed-up”.   So – what to do now?

I won’t go into details of how i discovered this, because most people just want the solution – so here it is.  Once your computer craps out at the black screen, shut it off by holding down the power button until you hear it click off.  Wait a few seconds, then boot it back up.  You should still have your windows CD in the drive, and when the EFI bootloader launches Windows, you should see a screen that says “press any key to boot from CD/DVD” – do it.  The little wireless keyboard sometimes goes to sleep – so hit enter a few times until you see the plain “Windows is loading files…” message with the ugly ASCII text progress bar.  If you see the “Starting Windows” animation with the windows logo – you missed it…. reboot and try again.

This will basically take you back into the Windows installer.  This time, you’re not installing, however – you want to get into Repair mode.  Follow the prompts and click through to Repair mode until you are prompted with a screen that has several options.  One of these options is “Command Prompt”, pick that.

This will drop you to a good ol’ DOS command prompt – I cannot remember the path it defaults to – but you’ll see a line that looks something like “X:\Folder1\Folder2>” where X is the drive letter and Folder1/Folder2 is your current location on that drive.  Without the quotes, type “C:” and press enter.  This will take you to your C: drive – the drive which Windows is installed upon.  Now, type (again, without the quotes) “del c:\windows\system32\drivers\atikmdag.sys” and press enter.  It should say “1 file(s) deleted”.  Peachy.  Type “exit” and press enter to exit the command prompt, and then click restart.

Now, your computer will go to the “starting windows” screen, and will advance to another graphic that says your computer is being prepared to be run for the first time – congrats – you’ve gotten past the black-screen-o-death.  Basically, what is happening is that Windows is detecting ATI graphics hardware in your shiny new 27″ iMac, but it’s installing an older ATI driver that is not compatible.  Once you get to the part where it tries to initialize the display – it hangs up.  When you delete this driver, you default it back to the standard plain vanilla VGA driver and things will progress smoothly.

Once you get logged in, insert the Mac OSX Install Disk into the DVD drive and wait for it to be recognized.  Click the start button, then my computer.  Double click the D: drive (it will say “WindowsSupport”) and allow boot camp to install all of the drivers for your machine.  You will most likely get a couple of times where the install will stop and ask you if you want to allow the software to make changes to your machine – of course, confirm this action.

When Boot Camp is done, your machine will need to be restarted.  Go ahead and restart, and then immediately run Windows Update by clicking it from the start menu.  This will install the CORRECT ATI drivers for your video card, and then your display will be available in it’s full glory.

Enjoy!

UPDATE 11/21/2010 – Some time ago, Apple has also created a support article regarding this issue – their solution is slighly simpler – http://support.apple.com/kb/TS3173