I want to update my PC, new in March 2004.Want to be able to play Microsoft flight simulator x and call of duty 4 without hang ups and artifacting.My PC spec is - CPU- Intel P4 3.2GHZ 800MHZ. Memory-512MB v/select PC3200. HDD-160GB 7200RPM.Graphics card-Radeon 9800Pro 128Mb.Motherboard-Asus P4S 800-SC-P4.I know I need to add more memory and a better Graphics card but do I also need to upgrade the CPU and if so to which one?. I think the HDD is OK at 160GB. I think the power supply will also need upgrading as well to suit a higher spec graphics card. Any advice will be most welcome.