About two weeks ago I went to turn on my pc and nothing. No lights no power at all. Checked the cables were plugged in and that all the power was on. Still nothing. I got it to work by reseating the 20pin power connector. It worked fine for an evening and then stopped the next day. I tried the same thing but this time could only get the fans to turn on. I kept checking the connections and psu (including resetting the voltage between 230 and 115 - which I believe caused the next problem) until it goes bang (literally) and I've basically fried it. I got a friend's spare one (It's an ATX12V PSU, at least 300W, i was using 400w but this spare is only 300w and I had used it before when he helped me build this computer and I didn't have a ATX12v psu) and plugged it in. First turn on (with a brand new power lead) I only got fans. Unplugged and replugged the leads and turned the power at the wall on and off and the power switch at the back of the computer. And it worked. Worked all day in fact. Last night I turn it on and get nothing so now I know the problem isn't the PSU, nor the leads (as both are new). This morning (nothing changed) I try it again and get full power. I turned off the computer but left the power at the wall turned on (with tape over it so that no-one would touch it) and when I got home this evening it turned on fine again. My assumptions are now that it is a motherboard problem as (from what I've read while trying to fix the problem) the motherboard controls whether or not the pc gets power even if the psu is working? At least in the case of ATX12v's ? Furthermore I have visual confirmation in the form of a tiny light at the back of the pc (amongst the sound, com, and rear usb ports) which is on when the psu has power - even when the computer has not been switched on. If the light is on then everything works fine, if it's not then it's not going to work. My motherboard is an MSI KT4A-V which came in this motherboard kit: http://www.savastore.com/productinfo/product.aspx?catalog_name=Savastore&product_id=10277601&pid=40&rstrat=3122 and if bought individually I think is this one: http://www.savastore.com/productinfo/product.aspx?catalog_name=Savastore&product_id=10248819&pid=44&rstrat=0 Any suggestions as to what would be causing the intermittent power will be most helpful, thank you.

Strangely seems like a power spike to me, does anything else work ???

Yeah everything works if it turns on at all. But if it doesn't work first time then nothing works until I switch on and off at the wall socket and try again (repeat until it works). Is there a power controller on the motherboard that might have burnt out or been shorted out?

Wattage means nothing if there's not enough amperage. There are plenty of crappy 400W units out there with just 10-12A on the +12v rail, & that simply won't cut it these days. On the flipside, there are some decent 300W units that will outperform many 400W units. With PSUs, you get what you pay for...a decent 400W unit with 18A on the +12v rail sells for at least $40 (US) When a PSUs blows, there's no telling what components it might take out with it. And just because a light comes on, that's no indication that the PSU is good...it just means it's putting out enough power to light the light. http://www.msicomputer.com/product/p_spec.asp?model=KT4AV-L&class=mb ASUS A7N8X-X Athlon XP 1800+ 8.5 x 200MHz 1024MB PC3200 2.5-3-3-7 Asus A9550GE/TD 128MB WinME/WinXP Pro SP2

Have you tried another power outlet?Have you tried another power cable from outlet to computer?Your power cord could be bad.

Take a real close look at the motherboard power connector. Look for any burnt connections.

You may have cooked your motherboard after toasting the power supply. If you don't know - don't touch things! You can avoid many of these Windows problems with Linux. Linspire eases the transition for new users