Direct to the point,Last night, my computer went off suddenly.History:1. Everything was working fine2. I turned off my computer3. Added a 10GB HDD4. Installing Windows XP SP2 on that 10GB HDD5. Computer turned off suddenly in the middle of installation without warningI observed:1. Motherboard LED is still on (Orange colored), but i noticed CPU and the rest stopped working (DVD-RW as well)2. I Tried to unplug the power cable and put it back on, didn't work3. Left it OFF overnight, and try again to turn it on, didn't work4. 10GB HDD removed, still won't work5. Removed all of my HDD and just left one for boot up, didn't work6. Did some research on the internet, they said something about Motherboard failure ( is this true? )Kindly please please please identify this problem... Thanks very muchHmm, do you have a power supply tester? Sometimes the power supply can die but still give off a faint enough charge for some of the leds to power on.Does it make any sound at all when you try to reboot? no lights or leds show any sign of life when you push the power button?it does not make any sound after i press power on, totally blank, but the motherboard's LED is on.My first attempt after sudden shutdown showed the CPU fan spinning for less than a second (it looks like trying to spin), the rest of the attempt showed the same, no spin, just motherboard's LED.and no, i dont have power supply testerOk, I think we can pinpoint the the problem to either power supply, mainboard or CPU. I personally think we can leave out power supply too, mostly you can hear and smell a power supply failure. Since there's an orange LED on mainboard, first thing I'd do is looking in the mainboard's manual and try to find out what that means.Another question: Did you overclock anything (cpu multi, vcore, fsb etc.) and what are your system specs?in 13 years I can say...PSU failure 95%HDD failure 3%MB Failure 2%You could even have a case where a PSU works but only some strands and not all died.Try another PSU first, then check MB.If you dont have a tester, unplug everything including MB, plug in a working hdd, start power. If the HDD sounds, then PSU works, else PSU dead.You didn't say how old your PC was. During the late 90's to early 00's, some motherboard manufacturers used inferior quality capacitors that were susceptible to leaking or bulging. Look at the tops of the capacitors, they should all be flat and shiney. If any of them are bowed up or have a substance on top, the caps are bad. In that case, repair is possible but not cost effective. You should replace the motherboard in that situation.Problem fixed, my power supply is DEAD. I tried with a different PSU.Another Question is: what should i consider when choosing the right power supply for my computer, im afraid of wrong power supply...How do i check it? Currently my motherboard is (Gigabyte)GA-7VT600.Thanks.Simply use any generic PSU of 300 W or more should do.I fyou have aload of hdd's you should add a 400 W PSU at least, perhaps 450.Anything else is overkill really, and you can easily do a $20 psu if youre strapped for cash.The PSU in that sense does not affect much, but get a good surge protector nevertheless, which you can get for about $5-$8 at any hw store.I have never had a problem with generic psu's, more look at size when your case is small.An ASUS pundit for instance you would be better off buying a new case than a psu as they are very expensive those small ones.I run 85 W PSU laptop with 3 USB devices and some external hdd's rather than anything, hooking it all to a usb attached keyboard/mouse and my monitor as a secondary screen.In this way, my tablet pc is my main machine, with the tablet folded up sideways behoind my monitor. Nice and quiet.For UK users (recount for your locale) a desktop online 24/7 costs about GBP25-40 per month.This is more valuable than anything when you leave your machine on for torrents.Look at your powerbill and take the price in $/kWh * (PSU capacity/1000) to find out how much you pay on your power bill.350 W should be more than enough, even a lot of hdds dont take that much power. The main power consumers are graphic-card(GPU) and CPU (again having your system specs would help a lot). Try to get a PSU with a high efficiency (there are certificates like 80+ bronce, silver and gold(best))is there any compability issue for PSU? like voltage, ampere, etc etc?