Heya all Wonder if anyone could possibly help? Mid November I built myself (for the first time) a computer and it was running wonderfully until about 2 weeks ago. What I mean by this is that it is constantly rebooting itself, with no input from myself, when I am either browsing the internet, or playing games like BF3/MW3/Kingdoms of Amalur: Reckoning. I have tried removing a ram block and it seemed to help for about 10 minutes until it then rebooted itself whilst I was playing a round of MW3. The error that I get is in the title (Error 41 - Kernel Power). No log is being created when the computer is rebooted automatically (have already checked this). I have run PSU calculators a plenty and they are saying I am in need of a 400w PSU and I am currently running a 550w PSU (after my 500w died a month or so ago!). Could the old PSU dying have had any effect on the current situation? Computer build is as follows: AMD Phenom II X4 840 3.2Ghz (not overclocked) ASRock M3A UCC Motherboard MSI Cyclone Edition 6850 (Factory Overclocked) 4GB DDR3 Kingston HyperX 1600Mhz RAM If you need anymore information, please don't hesitate to let me know! Thanks EDIT: Managed to solve this - was a BIOS update to my mobo that messed me up - lesson learnt the hard way !!!