Unstable 8.04 Freezes Periodically

Usually while using my wireless network for system updates or Firefox, Ubuntu freezes. The only way thing available to me when it does this is to hold down the power button on my laptop until it turns off. Also, I only seem to get my screen to update when the mouse moves. Things like the firefox page loading animation or the animated mouse pointer don'e move unless the mouse is actively moving. That's the only thing that seems to work.

I am using a Gateway 7510GX laptop and have sent in the hardware profile as a matter of habbit on a first installation. Most of the tests failed, including the video and the sound tests. 7.10 was VERY stable on my machine, but 8.04 is only usable for between 15 minutes and an hour before it freezes entirely. I have no output from these freezes because I can not do anything but move the mouse.

I am using the default sound drivers and restricted BCM43XX drivers as well as restricted Video drivers for the ATI Mobility X600 video card.

Note: I had this issue before installing the restricted video driver. and the freeze seems to coincide with a complete loss of signal from my wireless network, which works fine under Windows XP SP2 and Ubuntu 7.10 Desktop x86.