I've encountered a situation where the PC started freezing up and crashing much more frequently than before. I started getting BSOD's much more frequently than before. I have made some minor software updates but nothing major - no Windows updates. I do not surf the web off this particular PC - so it's very unlikely that there's a virus or malware present (and I do have Norton and MalwareBytes installed on this PC). I had a somewhat similar situation about 2 years ago when the PC started crashing inexplicably. At that point, I ran MemTest to ensure that my RAM was OK. It was OK. The PC miraculously stopped crashing after I formatted the harddrive and did a fresh Windows install. Everything was fine for the next 18 months or so. My most recent setup: Cooler Master 1,000W PSU, Gigabyte GA-P35-DS4 mobo, Intel Core 2 Quad 2.4 CPU, 4GB RAM, NVS440 Video, NVS290 Video. No overclocking - just stock settings. After the most recent wave of crashes, I switched motherboards. I currently have Asus P5N-D. I also switched hard drives. Yet I'm having the same crashes as before. I'm unable to even start the installation process for Windows XP Pro - the PC resets itself once the "Windows is starting up" sign appears. I ordered a new PSU ( Cooler Master M700) hoping that it might help things. In the meantime, I'd appreciate any thoughts as to what might be going on with my PC and how to fix it. Thank you.