OK, I have a big problem here. I was just surfing the web and changed some keys in the registry of Vista, to enable the Glass effect. I restarted the computer, but hit the SHUT DOWN button in the start menu instead, so it shut down. So I let it shut down, and then when I pressed the button to turn it back on, all the lights turned on for like half a second and shut off...didn't turn on...i press the power button again...again, lights on for half a second, no sound and shuts off. I shut it off on the back PSU switch and take out the cable, plug the cable back in, and turn the PSU on. I try to turn on again,and the lights turned on the neon and fans were lit up, CPU fan was going...everything seemed normal for the first 3 seconds, but I noticed there was no picture. I looked down and I started hearing the DVD Drive restarting, and then noticed that the HD Light kept turning on and off, which looked like the PC was turning off and on. I opened up the window and the hard drive was spinning and everything. I could not hear the CPU, but I heard the CD Drive and the Video Card fan also. I tried unplugging everything that was not needed, taking out the video card, taking out memory, reseting bios, vacuuming the dust, taking out CPU and putting it in again...same thing. I did notice that when I unplug the CD and DVD drive, the HD light in the front doesn't turn on at all and I hear no sounds from the CD/DVD drives, except the HD turning on and the fans. If anyone knows what this sounds like, please help! I am guessing it is mobo failure, or a CPU failure, or the PSU is having issues. I dont know if its the CPU because all of those neons and fans are still on full force, and all the drives are on. I don't know. Please help. -Dino

If you have stripped it back to bare PSU,Mobo,CPUwith HSF, 1 stick of ram, graphics and keyboard, and it still won't POST then one or more of those components has failed. Unload all the eye-candy off the powersupply as well. disconnect all drives and unplug any PCI cards. I used to have a signature but it disappeared and I just couldn't be bothered writing another so please feel free to ingore this.

Did you reset the BIOS?

Yes, I tried resetting the bios, and it didn't do anything. Same thing...black screen and red light blinking on monitor...it keeps restarting.

The registry tweaks had nothing to do with it...my guess is the PSU. Did you try Richard59's suggestion in response #1? 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

i've had the same problem before, turns out the capacitors on my mboard have ballooned; i replaced the whole mboard