Hello, I have encountered a problem regarding the power to my PC, so here's some background information regarding my diagnosis and steps taken: (scroll down all the way to see my queries). This computer has been running with this configuration for 8 months now. When I switch on my PC, it runs for a little while, but once it enters the Windows Desktop, the whole computer completely powers down abruptly, and when I press the power button it will refuse to turn on (even after multiple times) unless I let it 'rest' for several hours. This happened after I upgraded my NVIDIA graphics drivers for my Geforce GT 630 (which certainly isn't a powerful graphic card by any means, but more than enough for average gaming). So, I thought the graphics drivers were the problem. However, somehow every time I started up the computer it just would not be able to enter the desktop without shutting down abruptly. When I tried entering safe mode (including the command prompt option) and 'Load last known good configuration', it would not even enter the Windows Desktop, and it would just hang at the scrolling bars screen (The OS is Windows Vista 32-bit EN-US). Then, I decided that something must have gone wrong with the boot loader, and I loaded my Windows 7 System Repair disc. To my horror, I discovered that 500GB worth of data located in 2 folders in a 2TB disk had vanished. Thankfully, CHKDSK repaired the problem, and I also subsequently used CHKDSK to repair the boot partition. However... ...just as I was CHKDSKing another drive, the whole computer completely cut itself off again without warning. As a precaution to my data, I took 4 of my 5 hard disks offline by disconnecting their respective power cables, except for the system boot disk. I also thought that my current power configuration could have overloaded the power supply, so I took the trouble to reset the CMOS (literally plugging out the battery since there isn't a jumper on the motherboard like the older ones used to have), and also disconnected the RAM for 2 minutes. Unfortunately, the problem didn't abate and now the power cuts off immediately when the Windows 7 System Repair Disc is being read (i.e. When the DVD drive spins up to read the disc). Furthermore, when I try to power up after the power failure, spark sounds (the 'piak piak' sounds) can be heard from inside the chassis when I attempt to switch it on (which is damn scary.) So now, I really need to ask: 1) Should I still attempt to switch on the computer? 2) What exactly is causing the fault...? Is it actually the power supply being unable to supply the entire system, or is there a potential short circuit elsewhere? If the power supply is the cause, please recommend me the appropriate power loading in watts and I will use my own discretion for branding on my next purchase. 3) What steps can I take from this point, other than those mentioned above? Also, just posting a bit of info on the specs of the system, if you need to determine the loading to the power supply is adequate. (This computer is clearly nowhere near decent as many of you here... I know) Motherboard: GIGABYTE EP45-UD3LR http://www.gigabyte.com/products/product-page.aspx?pid=3286#ov Power Supply: SeaSonic 700W Power Supply RAM: 2x 2GB Corsair 1366 MHz Audio: Onboard 7.1 ch Realtek HD Audio 3 system fans, 1 CPU fan connected on board Peripherals: Graphics: Geforce GT630 1x LG DVD-RAM Writer 5x Hard disk drives (normal IDE/SATA, no RAID or AHCI) All disks are Seagate branded, in increasing order of capacity (40GB, 80GB, 160GB, 500GB, 2TB) (A fruit salad combination) 2x USB flash disks connected at boot No other peripherals connected. I am looking forward to some responses with regards to this issue. For now, I have kept the computer switched off, in case it's going to harm my data even more.