How do you change GPU voltage on your laptop (Acer 8935G)?

My Acer 8935G laptop is running a duel graphics card setup (AMD Mobility HD4670 and Intel) and has started crashing constantly to a state where it's cycling though solid colors when I'm running it on the regular AMD card.

It happens completely randomly when I'm for example running games or using the mouse scroll wheel and I've tried everything, including reinstalling Windows and changing external hardware/ports and so on and nothing makes any difference. Sometimes it's crashing every two minutes and sometimes every two days for whatever reason.

I've been investigating this for a couple months and I've come to the conclusion that it's a known 8935G error with the GPU that you might be able to resolve by simply decreasing the GPU voltage from 1.2000 volt to 1.1000 volt.

The only problem is that I can't find a software that accomplishes what I want, and I've tried:

• MSI Afterburner (won't let me touch the voltage slider no matter how I change the cfg file, possible driver issue but I've tried with two different drivers).
• ASUS GPU Tweak v2.0.26 (won't load my VGA driver).
• ATI Tray Tools (seems to work but gives me a BSOD for atitray.sys at boot when I restart).
• ATI GPU Clock Tool 0.9.26 (works but won't save the settings when I reboot and will only allow me to adjust the lower voltage setting, 0.9000 volt -> 1.1000 volt, and the computer will still switch up to the higher voltage setting, 1.2000 volt, and crash).
• ATI GPU Clock Tool 0.10.6.0 (won't let me adjust the voltage slider again).
• ATI GPU Clock Tool 0.10.12.0 (can't find it, who's distributing this software again?).

I've also tried clocking down the card but that doesn't make any difference.

Anyone have an idea about how to change the voltage to your GPU on a laptop like this? And how do you prevent the computer from switching up and down from 0.9000 volt to 1.2000 volt depending on usage? It doesn't seem like a power saving option.

Or should I just go for a cheap new graphics card (and if so which for a GM45/PM45 chipset)? I rather not do that since that costs money and might not resolve my situation.