I have a desktop computer with 256 MB of PC2100 DDR RAM. My motherboard has a capacity of 512 MB. I bought a stick of 256 MB PC2100/2700 DDR RAM. I turned off the computer and installed it in the slot. It snapped into place. I turned on the computer and I get a message saying the comp automatically configured itself for the addition of memory. But then it went to a black screen and did not complete the boot up process. During the boot process the screen had little flickers going on. After turning the computer back off and taking out the additional stick, it booted up and ran fine. What do you think the problem is?