Alright everybody.. Same situation for me. Two HD 4850's in crossfire mode.. I updated some drivers and started to get the BSOD with the atikmdag.sys error. I actually came up with a fix for this 4 hours later that doesn't require you to reformat your computer. In my case, here is exactly what I did:
- Start computer in safe mode with networking
- Download and install Driver Sweeper which can be obtained here
- Start the Driver Sweeper program, check the ATI - Display box and click on the Clean button. This will delete ALL ATI drivers from your system.
- Reboot computer again, it should start normally now if everything worked right... Now you're gonna remove any CCC program via add/remove programs.
- Now all you have to do is find the original driver you had before you tried to upgrade. I would recommend using the disk that came with your video card. You can also go to the ATI website and search for your exact model and download the drivers... Keep in mind, I would stay away from the newest versions of drivers as they all seem pretty buggy...
The current CCC software I am running stable is: Catalyst™ Control Center Version 2010.0406.2133.36843
The current driver I have installed for my HD 4850's in crossfire mode is atikmpag.sys (8.14.1.6113)
This driver with that version of CCC hasn't failed me yet. Try not updating graphics drivers if you don't have to. If it isn't broke, don't fix it.
I really hope this helps everybody out... I got mine working again... Oh and for all of you with the black borders issue the post above mine is 100% accurate and will fix the issue.
Also this is the system I am currently running:
SPECS:
Microsoft Windows 7 Professional 64-bit
AMD Phenom II X4 965 Black Edition Deneb 3.4GHz Socket AM3 125W Quad-Core Processor
ASUS M4A79XTD EVO AM3 AMD 790X ATX AMD Motherboard
Crucial Ballistix Tracer 6GB (3 x 2GB) 240-Pin DDR3 SDRAM DDR3 1333 (PC3 10600) Desktop Memory
XFX HD-485X-ZNFC Radeon HD 4850 1GB 256-bit DDR3 PCI Express 2.0 x16 x2 in crossfire hooked up via HDMI cable
ASUS VE246H Black 24" 2ms(GTG) HDMI Widescreen LCD Monitor
Seagate Barracuda 7200.11 ST31500341AS 1.5TB 7200 RPM SATA 3.0Gb/s 3.5" Internal Hard Drive