I recently replaced the faulty Radeon Mobility ATI X700 graphics card in my 5 year old M1437G and thought I would share the information.
The replacement card is a nVidia GeForce 8600M GT 512MB DDR2 MXM II VGA Card, with ACER BIOS. The new card did not have heatsink mountings so I also purchased a matching mounting plate. I also had to remove a small section of the heatsink as a component on the new card prevented the heatsink seating correctly.
Before re fitting the heatsink, I cleaned the fan and air vents, removed the original thermal pads and applied silver loaded heatsink paste to the CPU, GPU and memory chips.
On first powering up the laptop, it booted into Windows XP without any video problems but the video card was seen as a generic card in device manager. I have since downloaded and installed the correct nVidea drivers and all is still OK.