I recently purchased a new processor for my pc after I realised for the type of gaming I am into an AMD Athlon XP 2000+ is too slow. Along with the new processor I replaced the ram (details will follow). After sorting all the bios options the computer restarted fine, but once into windows it died... repeatedly and usually after the same amount of time. I eventually solved the problem by underclocking my processor too an Athlon 2200+ (not what i bought it for). I have replaced my 400 Watt power pack with a 550 Watt power pack, but the problem persists. Soon after I decided it was windows and reinstalled... and to begin with the computer ran fine, there were one or two stability problems. Shortly after it started up with the restarting again. This time though it only occurs when doing anything processor intensive or using the graphics card - ie games or winamp visualisations. Another noticable problem, when running Videos with the processor at 3000+ green dots appear on screen in clumps and in different places moving all the time. Yet at 2200+ it works fine. Mother Board: MSI KT4AV-L (6712) Processor: AMD Athlon XP 3000+ FSB 166mhz 512kb L2 Cache(OEM) (Currently running at 2200+ FSB 133mhz) Chipset: VIA KT400A CPU Fan-Heatsink: Cooler Master Aero 7+ RAM: 512MB Kingston DDR PC 2700 Graphics Card: NVidia Gforce 5600 (128MB, AGP 8x) HDD: Maxtor DiamondMax Plus9 80GB UDMA133 8mb Cache 7200RPM LG DVD-ROM/CD-RW combi Sound Card: Creative Sound Blaster Audigy LS Speakers: Creative P580 5.1 speakers LAN Card: Realtek RTL8139/810x Family Fast Ethernet NIC PSU: 550W WINPOWER SILENT PSU 12CM SPEED CONTROL FAN What I have already tried: Reinstalling WIN XP I have SP2 Graphics drivers up to date (61.77) Checked board compatability Replaced PSU (No change) Mess with all sorts of Bios settings (ie spread spectrum) And now I am stuck... I am contemplating updating my bios, but the update that is available is of no use. I am about 2 steps away from just scrapping the system and starting again. Can anyone please help me.