How do I fix Dragon Age 2 crash, severe lag on Windows 7?

System

Operating System: Windows 7 Home Premium 32-bit (6.1, Build 7600)

Processor: Intel(R) Core(TM) 2 Duo CPU T7500 @2.20GHz (2 CPUs), ~2.2GHz

Memory: 2048MB RAM

DirectX Version: DirectX 11



Display

Name: ATI Mobility Radeon HD 2400 XT



I read on http://social.bioware.com/forum/Dragon-Age-II/Dragon-Age-II-PC-Technical-Self-Help/UPDATED---DX11-known-issues-and-drivers-6420212-1.html that you have to install Catalyst 11.4 Early Preview. If that's correct, could someone please give step-by-step instructions on how to install? Thanks.How do I fix Dragon Age 2 crash, severe lag on Windows 7?
there are different reasons explaining the lagging problem, and also different solutions solving it. try this one and the game will run better.

http://www.copygames.org/game-tips/how-t鈥?/a>How do I fix Dragon Age 2 crash, severe lag on Windows 7?
Your video card is rubbish - New laptop time!