I just recently built a new gaming rig and everything seemed fine after installing WinXP and a couple games and playing for a few hours. After a while I decided to try out Nvidia's Ntune. Well I didn't like it so reverted back to the defaults and removed it. I also flashed the bios for my mobo earlier today. Now it seems whenever I go into a 3D game the PC will hard lock with looping sound at random times throughout gameplay. I've uninstalled just about everything and reinstalled it. Reset the bios back to defaults. Nothing is overclocked and yet it still continues to lock up. Any thoughts,ideas, etc would be appreciated. Here are the system specs: Amd Athlon64 3000+ SkT939 1.8GHz Venice Core Foxconn/Winfast NF4UK8AA-8EKRS Nforce4 Ultra 1GB G.Skill ValueRam PC3200 @ 2.5-3-3-6 Sapphire Radeon X800GTO 256MB PCI-e Soundblaster Audigy 2 ZS Seagate Barracuda 7200.7 Plus 160GB HD 8MB Cache Antec TX640B Enclosure/ SmartPower 2.0 400 watt PSU As far as driver versions go I used Catalyst 5.10 and the latest Omega drivers both with the same results. OS is WinXP SP2 with all hotfixes/updates. As far as games go it's been pretty much every game. Painkiller, any Steam app, WoW, America's Army etc. Other drivers as far as chipset, soundcard etc are all the latest.