Power Button Cycles on & off repeatedly without booting. [ Edited ]

[lzavertnik]

I have an HP Pavilion Elite HPE-490t, Product # XM559AV#ABA, Serial #[Personal Information Removed], Intel i7 processor, with 24 GB installed memory, OS Win7Pro 64 bit.

When I press the power button, it briefly lights up (white), but then cycles off (amber color, then shuts off (no light).  This all happens within 1-2 seconds.  It will wait about 5 seconds and repeat this cycle indefinitely.  Sometimes if I disconnect the power,  reconnect the power then press the power button it will proceed to a normal boot, but not always.  There seems to be no pattern to what action will allow a normal book.  I've checked the Hard Drive C and it seems okay.  I'm wondering if the problem is in the power button or maybe the power supply.  Any suggestion for eliminating various hardware problems?

[Danjen]

It could be the power supply, shorted device of any kind attached (bad printer, flash drive, keyboard, mouse, network connection), memory problem, video card fan not spinning and the video card could have overheated, bad capacitors (rounded or leaking a brown or dark substance). The first think you should do is make sure it is not under warrantee.  If it is, contact HP.  If it isn't, remove the cover and inspect the board for bad capacitors, fans not turning, disconnect all non essential items like the hard drive, DVD, floppy if you have one, all external devices (yes the monitor) and turn on the computer. Does it appear to stay on? If yes, shut it down by holding in the power button for 5 or more seconds or flipping the power switch on the power supply or pulling the plug. Connect the monitor and then one item at a time leaving the hard drive with your important data as the last item. If it didn't stay on. Try to use only one piece of memory and try each memory slot, try the next piece etc. If that doesn't work, the best guess is the power supply (if you have an ohm meter - test the power supply first).