My computer started to have problems several months ago. The screen would go blank and the computer would freeze and could only be hard shut down (hold down power key) and the computer could not restart right away it needed at least 10 minutes before it would restart fully. After many many attempts to repair the problems and there was more than one problem (Cmos battery dying, damaged wire in laptop hinge, etc.) I finally was able to determine that the error that caused the crashes seemed to be a driver from doing internet searches on the errors Atikmdag 43029 and 52236 (event viewer). Many solutions were proposed and tried (about 40 hours actually working on this one problem), but until tonight none actually worked so I thought I would share the solution I eventually discovered.
My computer: (purchased in 2010)
Toshiba Laptop Model: PSLXJC-00Q005 - Satellite L550D - 00Q with AMD M860G with ATI
Mobility Radeon® 4100 Graphics and 4 Gb of memory 500 Gb storage with windows 7 32 bit.
1) Open windows explorer and go to c:\windows\system32\drivers and look at the file atikmdag.sys it will have a date more than likely in 2009 (in my case).
2) In Device Manger go to Display Adapter and uninstall driver. Use vga driver instead.
3) Use while in safe mode use free graphics driver uninstaller program DDU v126.96.36.199.exe.
4) Use free registry cleaner CCleaner several times and purge as much as possible after making back up of registry.
5) Install legacy win 7 catalyst software and drivers (13-9-legacy_vista_win7_32_dd_ccc_whql.exe).
6) In device manager go to Display Adapter and update driver when it prompts you where to scan for driver select on my hard drive and browse to C:/AMD/support/13-9_legacy_vista_win7_32_dd_ccc directory (default install directory) and select it.
7) It will search for driver and Install it.
9) Open windows explorer and go to c:\windows\system32\drivers and look at the file atikmdag.sys it will have a date now that is in 2013
10) Use event viewer to check if the Atikmdag errors have reoccurred. They should not have reoccurred.
For awhile there I figured my computer was done, but I had to give it a real hard try as I cannot afford a new computer. I hope this helps as some of the solutions around were pretty exotic and could damage your computer