Hi there, It's all about my friend's PC and it has the following configuration: MB: Asus P5B-E CPU: Intel Core 2 Duo E6420 RAM: 2X Kingmax 512MB DDR2 667MHz => 1GB VGA: Nvidia GeForce 7300le OS: Windows 7 Ultimate x86 The first thing i want to do is to buy a new single RAM memory of 2 GB at 800MHz, because personally I think that the RAM is the weak link of the system. The first question is: What is the best combination? To have 3GB of RAM at 667MHz or 2GB at 800MHz......? Now with the currently configuration (1GB at 667MHz) the level of used RAM memory in idle is 75%. The other problem is that every time when the PC is shutting down, the green light turns off and the red one is blinking very fast, giving you the impression that it's always lit; and the red light intensity is very low; (it emits less light). The PC has 2 coolers (one for CPU and other to the power source ...and the VGA doesn't have a cooler) and when the PC is shutting down the phenomenon with the lights happens and one of the coolers will never stop (i don't know which of them)... => the red light is blinking very fast at low light intensity and a cooler is on.....and those will never end up until you will press the shut down button for a few seconds. The system was configured (installed the OS and the other programs)... by a guy with knowledge and he said that this happens because of the newer OS installed. (Windows 7). This problem doesn't appear when restarting the PC.... It appears only when the system is shutting down. The second question is: Can the small capacity of RAM (1GB) lead to this phenomenon?