I'm having a really strange RAM issue, and not one that I've really seen anyone else talking about. First of all, the details....I believe I have a MSI 845 Ultra-AR (MS-6398) mother board and am trying to install a 512 MB DDR PC-2100 266 Mhz module DIMM ram. My computer is a school supplied Tangent computer that I'm trying to upgrade and only came with 256 MB of ram. When I install the 512 MB ram (I made sure it was the exact same type of RAM, just bigger) my computer runs absolutely perfectly fine....as if the 256 MB ram was still in. When the computer loads, it still claims that I am running 256 MB ram. When I check my bios, still claims its 256 MB. No crashes or anything, just does not work the way it should. I have tried installing the ram into every slot, and still nothing, it does the exact same thing. When I install the 512 with the 256, my computer really goes nuts, claims i'm running 1.2 something gig of ram and then crashes before windows can load. I've called the University Help Desk, and their only advice was to try putting it in different slots, which I already have done, so I guess I'm just asking for any kind of help that can be offered, Thanks!!