|If you not done so already, go to the Corsair web site and look up the ram that is listed for (is definately compatible with) your mboard model by using your mboard brand and model to search with.|
If whatever the part number of your Corsair XMS2 DDR2-1066 is not listed, it MAY or MAY NOT work properly in your mboard.
If it IS listed, it should work fine in your mboard.
If it's NOT listed, it MAY work fine at 800mhz but NOT at 1066mhz, or it may just not work properly.
A common thing that can happen with ram, even ram that worked fine previously, is the ram has, or has developed, a poor connection in it's slot(s).
This usually happens a long time after the ram was installed, but it can happen with new ram, or after moving the computer case from one place to another, and I've had even new modules that needed to have their contacts cleaned.
See response 2 in this - try cleaning the contacts on the ram modules, and making sure the modules are properly seated:
Assuming the ram you have is listed....
Either find the timing numbers that are printed on your Corsair XMS2 DDR2-1066 modules, or find that in the specs for the exact same part number.
Go into the mboard's bios Setup and load Optimized Defaults, or similar, save settings.
Go into the bios Setup again and make sure your cpu model is running at the speed it is designed to run at, and find the place where the ram timing numbers are shown - those timing numbers should match the timing numbers on / for the ram modules, if those are the only modules you have installed.
NOTE that some bioses default to running the ram at 800mhz even when you have a cpu that you can use 1066mhz ram with and you have installed 1066mhz ram, and in that case you must change some setting to get it to run at 1066mhz.
Your cpu must support using 1066 mhz ram with it - if it doesn't you must run the ram at 800mhz. The timing numbers only apply to when the ram is running at 1066mhz.
If everything is right except the ram timing numbers, you can change those manually in Setup to match the specs of the modules, or as close as you can get with numbers that are HIGHER (slower).
Your particular video card requires a lot of power.
Your power supply must have at least the minimum capacity required to support a system with the graphics card you are using installed, or the max graphics card you might install in the future.
(Onboard video - video built into the mboard - IS NOT A CARD!)
You can go to the video card maker's web site and look up the specs for the model - often under system requirements - the minimum PS wattage, and, more important, the minimum amperage the PS must supply at 12v is stated. If you don't find that, any card with the same video chipset including any letters after the model number has very similar minimum PS requirements.