i just got a new motherboard with 4gb ddr2 800 memory, amd sempron le 1250 2.2ghz 160gb harddrive, but even after a fresh installation is running very slow and the processor is almost always on 100%. youtube videos are sticking and browsing can be very difficult, and to make things worse if i install my ati 6570 card it becomes even more slow. any ideas as to what could be the problem..