I just installed a second 256 DIMM into my pc....the pc will still boot, which means it must be seated properly...ive also checked numerous times to make sure it didnt wiggle out or anything.....but i dont think my pc is recognizing the DIMM....has anyone else had this problem or am i just missing something simple??? any help is apperciated. Thanks.

You dont think it recognized?..or you know for sure it didnt recognize the RAM? Check your system properties to find out how much RAM is showing.(>Control panel >system ..it is listed at the bottom). If the RAM total isnt what you have installed, then it may be either an unsupported type/capacity, or perhaps the installation method. Some Computers need to be physically unplugged from the power for a few minutes before installing the RAM (recommended anyway). Some boards you may have to reset the CMOS to recognize the new RAM. If you decide to reset the CMOS,however, it is recommended you enter the CMOS setup first and write down the settings so you can always change the settings back if you encounter problems with your hardware. Read the instructions for your mainboard to see if there are any specific steps such as these that may be required when upgrading RAM. Good Luck.