Temperature is high with AMD Athlon(tm) XP 2400+

Environment: I've a AMD Athlon XP 2400+, MSI MS-6390 motherboard, 1.5 GB Transcend RAM (2 DIMMs-1 GB, 512 MB (400 Mhz), 3 Seagate HDDs - 40 GB, 80 GB, 160GB, Graphics card: nVidia GeForce 6200 AGP card, Chassis: Mercury KOB 146 with 450W PS, 1 processor fan (default), 3 system fans 1 for inlet, 1 for outlet, 1 to cool HDDs, 1 Liteon DVD drive. Ag. room temperature: 28 C(approx. 82.4 F).

Issue: On comp startup (in BIOS) the CPU temperature is around 53 C(127.4 F. But on complete boot and at the desktop the temp is around 65 C(149 F). If any game like NFS UG2 is played at lowest details then the tempearture can go upto 70 C(158 F). The GPU temp at normal desktop is around 48 C(118.4 F), after the game is played the temp goes upto 56 C(132.8 F).

Question: What can be done to reduce the temperature both of the CPU and GPU? Any idea is welcome suggestion!!! Please help