by Stupot » Fri Oct 28, 2011 15:42
Sounds like one of two things is happening.
Either some application has gone crazy and sucked up all your RAM, or one (or some) of your sticks of RAM aren't working properly.
I ran into a similar issue with my box when 2 sticks of RAM would sometimes work and sometimes just stop working. I had to scale back to using 2 GB instead of 4 GB to make my system stable.