Unable to install old laptop ATI mobility drivers X600 on Windows 8

So, after a few hours lost, I found a way to get it work, and here is how I did it in case anyone else is interested:

First you need a working Windows7 machine (32 bit or 64 bit won't matter). Then:

1. Downloaded an old Catalyst Driver 9.3 WHQL for Vista/Windows7 (64bit, 32bit)
2. Execute the file and start installing until files are extracted to the C:\ATI path , then abort.
3. Download Mobility Modder program and install it.
4. Launch Mobility Moder and browse to the folder where you extracted the drivers, clic mod and let it do it.
5. Copy the modified drivers to your W8 machine.

Now, on your W8 machine:

1. Clic start, type: "Device Manager", clic on it.
2. Find the Generic Display Driver under "Display Adapters" (sorry if that's not the exact wording).
3. Right clic on it, then "Update driver Software"
4. Then choose "Browse my Computer Software", and choose the path to your modified driver. During installation you'll be warned that the driver is not "digitally signed", don't worry and keep going (that comes as a result of the modification).

And that's it, at least in my old VAIO laptop (2005 model) that resulted on a perfectly working and stable driver, with decent Windows performance Index of 3.9 and 3.7 for graphics.

Warnings:

• Mobility Moder doesn't work on W8, so if you don't have another computer be sure to get the work done BEFORE you upgrade.
• Others have suggested to install up to Catalyst 10.2 (you can download from the same site). Have not tried yet, but if I were you I would prepare both before upgrading to W8.