Yelläks /ˈyæl•eks/

AMD/ATI does not provide Catalyst drivers (Windows) for its graphic adapters in laptops. The Mobility product line is only supported through notebook manufacturers and hence someone has to download the drivers from the websites of e.g. Dell, Acer, ASUS, etc. But what if the drivers are outdated or worse, if a Mobility Radeon is built into a laptop that is not designed to have one? The politics of nVidia is different and everybody von a nVidia graphics adapter can download and use the nVidia driver. Honestly I assumed the same applies for ATI drivers and it took me some time that Radeon HD3650 mentioned in the supported devices list of Catalyst does not mean Mobility Radeon HD3650.

To install the Catalyst driver anyway, I needed to follow these steps (it was a clean Windows installation, so maybe you have to get rid of an old driver first):

1. You need the Catalyst driver. Current is 10.2, but it is not supported in DH Mobility Modder.NET. The team is working on that though. Instead I downloaded Catalyst 9.12 (for Windows XP). There are also Omegadrivers maybe you want to try out one of those.
2. Start the installation of Catalyst, but interrupt the process, when the first dialog comes up after all files got decompressed. Now all the installation files are in C:\ATI\support\9-12_xp32_dd_ccc_wdm_enu (or any other directory that you chose).
3. Download and install DH Mobility Modder.NET (have a look at the compatibility list mentioned on this side). You need Microsoft .NET Framework 3.5 SP1 (online/offline installer) and MSXML 6.0 to run this program.
4. Point DH Mobility Modder.NET to the files in the directory stated above and let it process the data.
5. Execute setup.exe located in C:\ATI\support\9-12_xp32_dd_ccc_wdm_enu\Driver\. That will install the Catalyst Control Center (CCC). However the driver (and hence the most important part) fails to install due to the unsigned driver (missing certificate) as stated in the protocol. Furthermore, you might run into the problem that nothing can be installed at all and the installation process aborts with an error (I had the experience in 10.2, but I do not know, if it also occurs in 9.12). If it fails (error message: “Catalyst Install Manager has failed”), you should check this thread. By applying this patch (the filename starts with the language e.g. CHS = Chinese Simplified, ENG = English, etc and ends with the architecture: x86 = 32bit systems, x64 = 64bit systems), the installation worked on a clean Windows XP professional 32bit installation without hassle. However there are users who report crashes in various other applications after applying the patch.
6. After installation is done and the driver is not installed, go to your Device Manager and update the driver manually. For that you choose the location of the driver to be in C:\ATI\support\9-12_xp32_dd_ccc_wdm_enu\Driver\Packages\Drivers\Display\XP_INF\. Confirm the unsigned drivers. Now the installation will be completed successfully.

[Update 16/04/2010]
The information given above is not up-to-date anymore. Since the release of Catalyst 10.3, it also supports Mobility Chips natively without the necessity to patch the drivers with DH Mobility Modder.NET.