Hi, This is my first post. Recently I have been having trouble when starting up my PC. When I press the power button it would light up, the fans would start up, and then in a few seconds the whole thing would power down before anything shows on the screen, then on its own it would run through the same cycle over and over again, powering up and down until I turned off the PSU. I did a google search and found advice to disconnect everything, reconnect it, and clear the cmos either by removing the MOBO battery or changing the pins on the reset cmos. I did all that and it started up again. I had the PC on overnight and when I returned to it the screen was blank (power saving mode), but I could not get the monitor to respond as the mouse and keyboard where unresponsive. I powered down manually and then it would not start again. I ran through what I did previously, but this time it did not work. I tried disconnecting the HDD's and the CD ROM drive and power on to BIOS. This worked. Then reconnected all the drives and it powered up just fine. I am using it now. I am perplexed as to why it works some times and not others. Could it be the MOBO or the PSU? I am, dual booting Ubuntu and XP. It loads to GRUB. Thanks in advance.