Posted by: Rajesh Kanaparti | November 27, 2011

Apple iMac 27″ Black Screen problem right after installing windows 7

Ok this is not the first time I am facing this issue of nothing but black screen right after I install the win 7 on my awesome 27″ imac. Today I wiped out and installed everything from scratch. Totally forgot about this black screen issue. So its time to note down the steps to fix this issue. The problem is with ATI graphics card. So we need to delete that driver to go back to plain vanilla driver for windows 7 to complete installation and boot. Once we get there , we can fix the resolution issue.

1. When you restart the iMac, you must be seeing a black screen.

2. Now insert the win 7 installation cd and restart. After press any key to boot instruction, press F8

3. Now you should be seeing windows is loading files progress bar. Keep pressing F8 until you see a command prompt with options. Go head and select “Start in Safe mode” option. Now you should see windows installation wizard. I know it is really confusing as all you want is to go to the repair mode. Dont worry, go ahead and select “Next” in the wizard.

4. Now this screen should have Repair mode options. Select that option and hit next

5. You will be that windows is loading and files and you will see a screen with options. One of them being “Start Command” prompt. Hit that button

6. You will see good old command prompt. Now enter c: and hit enter

7. After that type the following in the command line and hit enter

“”del c:\windows\system32\drivers\atikmdag.sys”

8. To double check that the file atikmdag.sys (which is causing the black screen) doesn’t exist, type cd windows/system32/drivers and hit enter

9. Type the following command

dir ati*

10. In the list of the file that are displayed, you shouldn’t see atikmdag.sys file.

11. Ok now click on the restart button

12. This time you should see that windows starts normally.

13. Wait not done yet. You must have observed that the resolution is horrible. Let’s fix that.

14. Insert the Mac osx installation disk and double click on the disk drive.

15. You should see a dialog box prompting if you want to allow Boot Camp. Click Yes

16.  If you installed a 32 bit version you can continue installing the BootCamp, or else  if yours is a 64 bit installation, you will get an error “Boot Camp x64 is unsupported on this computer model”. Common !

17. So open the cd/dvd rom drive by going to start-> Computer and then right clicking on the cd/dvd drive.

18. Go to boothcamp->drivers->apple directory

19. Find the BootCamp64.msi file and right click on it. From the options , select Troubleshoot Compatability

20. You will see a dialog box with “Test Compatability settings for the program” and “Start the Program” button. Go ahead and click on that button.

21. Now you will see the bootcamp wizard. If you are prompted with Yes/No options during the wizard, select “Yes”

22. Basically this is installing all the drivers needed for windows

Now enjoy the high resolution screen with your windows 7.








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