I press the start button on my computer (from cold) and the computer begins to start up - the hard-drive light comes on and the fans start - but then after just something like three seconds it shuts down again. If I press the start button immediately after the computer remains dead - I seem to need to disconnect the mains supply at the house power-point (i.e. pull the plug out the wall), wait about 15 seconds or so and then try again. Sometimes the computer will start normally first time, sometimes I have to repeat the above procedure half-a-dozen times. Once running there is no problem - no power shutdowns whatsoever. The only similar problem I've seen posted on the net is at: http://forums.computeractive.co.uk/thread.jsp?forum=7&thread=74550 I'm using Debian Linux incidentally but am not sure whether the problem is anything as "far in" as the motherboard let alone the software - though something is detecting the power applied to the computer and capable of timing its presence to some extent at least. It's probably not annoying enough to go out and buy a new PSU yet, but if it does get worse I would very much like to know where to look. TIA for any help.
My machine specs: 2GHz Celeron; 256MB DDR PC3200 RAM; 40MB Maxtor 7200rpm HD; Shuttle AV49VN Motherboard; Case/PSU 9950W Midi Tower ATX, 350W PSU, 20pin PSU Connector (http://www.cclonline.com/product-info.asp?product_id=73&category_id=52&manufacturer) Recently replaced the PSU fan with new Silenx 9dba 18cfm fan - old one making inordinate noise, but don't think revs had depleted significantly (except when I "twanged" it with a piece of card to make it stop and start again in a quieter mode!) Machine age: 2 years (just over) Machine usage: About 6-8 hours per day (guess)
I would make sure that your CPU heatsink is properly installed with either a thermal pad or thermal paste. If that fails to fix the problem, then look at the Power supply.
You might have a simple case of 'chip creek'. Your hardware is constantly getting warm and therefore expands - sometimes enough to move it ever-so-slightly out of it's slot. This is especially true on older systems. It is usually the cause for strange PC behaviour, like you are experiencing. All you need to do is re-seat all of your hardware. Another cause might simply be dust. Dust can cause strange PC behaviour. Make sure your have checked for chip creek and dust before you go out and buy new hardware.
Your PC might be overheating so check all your temps, graphics card, CPU, the works. Second, your PC might be under-powered by your PSU. I would first rule out temperatures, and then look into getting a better PSU.