I upgraded my PC to 512MB RAM yesterday and since then internet explorer and word has crashed once saying cannot access memory address then a hexadecimal location. I could live with this but I am worried this may happen when I am doing some work. I have 2 x 256MB DDR PC2700 modules installed but both are not identical. The problem is the shop I got in from have stupid return policies and will just say my problem is due to a compabaity issue.