Black Screen after Windows 7 32bit boots

Hello,

I have a mid-2011 27" iMac with AMD 6900M Series card and I am trying make Windows 7 32bit work.

I have succesfully installed Windows using BootCamp, after it booted I have installed BootCamp drivers and restarted Windows. But then the screen went all black.

I booted into safe mode and deleted atikmdag.sys and rebooted again. Windows boot perfectly, but I cannot max out the resolution and Aero is of course not working.

So I have cleaned ATI/AMD drivers from the system using DriverSweeper and tried installing BootCamp drivers again with the same result.

So I wiped them again from the system and tried using graphics drivers from AMD website. I downloaded 13.9 driver and installed it, with the same result again.

BootCamp drivers I have found are 4.0.4033. I could not download drivers using BootCamp assistant in OS X because it is running OS X 10.9 and BootCamp 5 and it only downloaded 64 bit drivers. This iMac was running 7 32bit perfectly some time ago. Installing 64 bit Windows is not an option.

I am a little out of ideas. Can any of you guys help me plz?

Which exact windows version do you have?

Windows 7 Professional 32 bit box.

Boot Camp 5 only supports 64 bit versions of Windows now. That's why it downloaded 64 bit drivers only.

I have a mid-2011 27" iMac with AMD 6900M Series card and I am trying make Windows 7 32bit work.

Click to expand...

Member MacDuck is right on target. You can not run the 32 bit version of Windows 7 on your machine with those drivers. Switch to the 64 bit version. I don't know why you would even consider running a 32 bit version as it limits memory and you have a 64 bit machine.

But the machine supports bootcamp 4 and 5 and 32 and 64 bit
Boot Camp: System requirements for Microsoft Windows operating systems
The OP used the bootcamp 4 drivers.

Sure you can question the use of 32bit but the is still a raft of commercial software that insists on 32bit. Don't know if that's the reason..... But it's a reason nonetheless

Another reason he's getting the black screen may be that he's not downloading the mobile drivers which his machine needs. The AMD 6900M is a mobility card, not a desktop card, and that fact usually results in the wrong drivers being downloaded. People forget that an iMac is nothing more than a large notebook computer standing vertically.

However, while you're correct about his machine supporting 32 bit, unless he absolutely needs to run in 32 bit mode because of some software incompatibility, he should run 64 bit.

BTW, I haven't run into any major Windows software that would not run in the 64 bit mode of Windows 7. However, I'm sure there still are some software publishers who remain behind the times.

I agree 64 bit is the way to go, but I know we(as a company) are constrained to using many of Autodesks products at 32bit because replacing them with their 64bit counterparts is cost prohibitive.

It could be a mobile, non mobile issue if the OP has manually selected the driver but ATIs standard offering now is a small detection app that downloads the correct driver as appropriate.

My instinct, if 64bit is off the table is to rip it up and start again

Thank you all for suggestions!

This iMac is not mine, one of the clients uses specific software that requires Windows 7 32bit (not my choice anyway ).

Anyway, I have installed all drivers again (4.0.4033) and turned it off. I cleared NVRAM and SMC and turned it on again. Surprisingly it booted just fine but when I tried turned on Aero the screen started to flicker and went dark again. Then I thought: there must be sth wrong with the graphics card. I rebooted to OS X and when I started stress testing GPU the screen started to flicker again and went dark again.

So everytime the GPU load rises above certain level, graphics card goes crazy. So now whenever I boot to OS X everything is fine until I run some tests. Under Windows it is also fine unless tests it as well.

All in all, weird symptoms, but this iMac is simply broken.

Thanks again for help!