|- The E6400 is a 1066MHz FSB CPU. You should be running either DDR2-533 or DDR2-1066 RAM. PC5400 = DDR2-667, so you're already running the wrong RAM. PC6400 = DDR2-800, so that's wrong as well. Just keep your DDR2-667 & underclock it to 533MHz, that will put it in sync with the CPU & provide optimal performance.|
- You didn't state how much RAM you have? Can't advise you about Win7 unless you list ALL your specs.
- You didn't state the make/model of your video card either. Gaming relies heavily on the graphics card. If the card is crap, the gaming experience will suck, & some games will be unplayable.
- 32-bit software works on either 32-bit or 64-bit systems. No tricks are required.