Hello There, I'm new to the forums, I normally don't go making posts (because pretty much all the time I search for something, someone else already has an answer). I got a problem with my computer. Here's the specs: 64 Bit Windows 7 Ultimate PSU: OCZ StealthX 600W CPU: AMD 64 Phenom X4 9650 Heatsink: CoolerMaster (not stock) RAM: (8GB) 4X2GB OCZ DDR2-6400 Platinum Video: XFX Radeon HD 5770 850MHZ 1GB 4.8GHZ Sound: Sound Blaster X-Fi ExtremeGamer & Sound Blaster X-Fi Extreme Audio HDD: 1X340GB & 1X500GB SATAII My computer has recently started shutting down on it's own. I have my PC running 24/7 doing multiple things at all times (I broadcast three radio stations amongst many other programs) - Although, with my specs it barely uses up 25% of system resources at any given time. It started happening around the same time my PSU went bad. I thought the cause at that time was my CPU. I tested it and it was infact dead. I got myself another one locally and RMA's the OCZ one. The computer actually ran fine for a while and then it started happening again. I though maybe it was a coincidence since the PSU I got locally wasn't as a high quality I had (maybe not pumping enough power). I then decided to take that one out and put my new OCZ PSU back in. This is same 600W model but a replacement. My computer ran ok for a little while but then a big heatwave hit and we were getting around 30-35 C (90F) - and my computer started shutting down again. I honestly didn't think it was a PSU issue anymore as each time it turned down I had to wait a while before turning it back on. So my next guest was obvious, OVERHEATING. I downloaded SpeedFan and noticed immeditaly that my CPU was averaging in the 50-60C and my GPU was at 65-80. I thought I nailed it at that point. so I ordered a new Video CArd (It was due for an upgrade anyways) and also a heatsink/fan from CoolerMaster (Very good reviews). Such bad luck, it took a couple days to get here and during that time I figured I'd keep using my PC as best as possible - but the very next day my Video card jsut crapped out and my PC would no longer boot/POST. When I took it out it worked. I waited until I got my new ATI Radeon HD5770 and put that in with the CoolerMaster heatsink. MY PC then booted up normally without a problem. First thing I did was start up SpeedFan and checked tempatures. WOOHOO! CPU and GPU are contantly running 35-40 C. I really thought I had it fixed. This was done Monday... It's now Thursday and my PC shut down this morning. I couldn't start it up immediately as normal but when I did my first thing was SpeedFan - All temps were normal. I kept an eye on it, not one hour later it shut down agaain at normal temp. Skeptical, I waited and this time decided to do a RAM test. The test was running normally with no error and when I tried to cancel out of it (Continuous test) - PC Shut down. Waited a few minutes and tried again. This time I watched the temp in the BIOS and they were infact 35-40C. I pretty much ruled out heat issue as I keep my inside very clean (I'm a qualified technician, full time job) so I'm extremely comfortable doing anything in the PC. I also blow the dust out of it regularly. I have everything connected to a commercial grade APC Surgeprotector which indicates no error - I also tested for fault on both the APC unit and the wall outlet with no problems. I'm thinking RAMs/MB - I'm basically looking for a second (or more) opinions. What do you guys think?