I'm at a loss with this one. Running Gigabyte GA-5AX Rev 5.2 mobo w/ 500 MHz K6-2 without problems of any sort for going on 2 years. Three SDRAM slots-which, up until yesterday had 2 64MB sticks and a 128MB stick occupying them. Decided to break loose of $20 and attempted install of 256MB stick of PNY RAM. Installed by itself, or in any variety of combinations with other RAM and this thing allows the BIOS mem test and reports back as a 512 stick. Then the system comes to a screeching halt. Took the PNY and traded for equiv amount of Centron RAM-same issue. Fault appears to lie within the mobo, but I have experimented with any number of BIOS setting changes and every on-board jumper variation you can imagine, but alas, NADA. Any thoughts ?