I put two new sticks of 512 Crucial 2100 DDR SDRAM CL 2.5 on my MSI KT266 Pro2 running XP Home and Athlon XP 2100+. The two new sticks are in addition to the 512 Samsung (CL 2.5) that was already there. It seemed to run okay for awhile, then I got a blue screen that I have never seen before, with all kinds of dire warnings about serious consequences if I did not figure out what the problem was. Of course there were no hints about what the problem might be, but, being the sharp guy that I used to think I was, I rewound to the last change I made. So I took out one stick and, again, it ran okay, until I got the blue screen again. I couldn't do anything to make the message stop recylcling without eventually unplugging the machine. So I took out the other stick, and have not seen the blue screen in the last two weeks since. I'd like to use this RAM, but I'm spooked now. Does anybody have an idea about what the problem is, and the remedy? Thanks