Ubuntu :: Machine Cannot Go 24 Hours Without Freezing

I have been battling with my machine for a while now, it cannot go 24 hours without freezing, I leave it on at night and in the morning it is frozen. I want to use it as a content server to my mobile devices but I have to be home to use it because it always needs a reset. I did a memtest and there were many errors, I realized that my ram voltages were under the min req. I boosted the voltage and ran memtest for 48 hours, no errors. This machine used to be stable for over two years, same hardware, I switched the case and now it wont last a day.

I am running 10.10 64bit, I would post log files but I dont know which one would be useful. I believe it becomes unstable when the screensaver activates. Also sometimes it wont fully boot but will go to the command line and other times it will give random error messages when grub is trying to load. Every week I solve one problem and then something else goes wrong. I have been using ubuntu since hardy on this machine and only lately (10.04 & 10.10) have the problems been occurring.