It worked in Windows 8, but it won't start anymore!
No yellow triangles in the Device Manager.
Computer: Inspiron 7250
Note: This laptop has Integrated graphics. It has Intel HD Graphics 4000 + AMD Radeon 7700M Series graphics cards.
May 24, 2014 Edit: If you can't reinstall AMD using the answer below, just try searching the web for the latest drivers.
If you still need help, download this: http://ftp.dell.com/FOLDER01725911M/1/Video_Driver_9NNDW_WN_13.151.0.0_A00.EXE
and this: http://ftp.dell.com/FOLDER01708967M/1/Video_Driver_KK6CK_WN_10.18.10.3277_A00.EXE
The first link is the download for the Radeon driver, and the second one is the Intel driver. They both need to be installed for everything to work properly.