Close programs to prevent information loss

I am using computer with configuration intel®core (TM)i7-3770 cpu@ 3.40GHz 3.40GHz ,RAM 8GB with 64 bit operating system, (cross)64-based processor and I am using R2011b Matlab 64 bits.After running 4 hours the error came ... Close program to prevent information loss. Your computer is low on memory, save your files and close these programe Matlab (R2011b). The bottom line of the command is windows will only close enough programs to restore needed memory.So please give some suggestion to solve problem .