I have searched for threads discussing this topic, but have not found any with the same symptoms. I had no problems on XP. Win7 was fine for a few months, but now:
When I shut down or hibernate, the computer turns off as normal. However, when I next push the front power button to turn the computer on, the LEDs come on, the hard disk and fans spin up, but the computer hangs. The monitor detects no signal and goes to sleep. It appears that the computer isn't even POSTing. Ctrl-Alt-Del and the front panel reset button do nothing. If I press the front power button for ~4 seconds, the computer turns off. If I wait a few seconds and then press the power button again it usually POSTs and boots to Windows normally. (Sometimes it seems turning the power supply off at the back is necessary to get it to boot the next time.)
Windows runs normally with no issues. Every time I shut down or hibernate the computer, this happens on the next attempt to boot! No problems resuming from sleep; rebooting from within Windows also works just fine.
BIOS is up to date (F13). AHCI enabled, although the motherboard only supports AHCI 1.0b. I have tried clearing the CMOS (jumper, didn't remove the battery) with no change.
I thought it was either a video driver or a chipset/AHCI problem since the problem appeared at some point after updating those drivers, and they have been implicated in power management/boot issues. Have tried two different Microsoft WDDM video drivers as well as the latest nVidia drivers with no change in the problem. Have tried Gigabyte's and Intel's chipset driver packages with no change. Disabled hibernation, no change. "Allow this device to wake the computer" is unchecked for all devices.
Any ideas or links to discussions of this kind of problem will be appreciated!
Windows 7 Professional 64-bit, all important Windows Updates applied
Core 2 Duo E6550
Gigabyte GA-P35-DS3R motherboard (Intel P35 Express chipset with ICH9R southbridge)
Video card: NVIDIA GeForce 7300 SE/7200 GS
Hard disks: Western Digital WD5000AAKS 500 GB (SATA),
eSATA WD 1TB external hard disk (not connected at boot)
Dell USB keyboard/MS USB Wheel Mouse Optical
Have you changed anything recently inside your system? I'm thinking your power switch lead may be out of position on the cluster of pins with this and power led, reset, etc. If your case uses individual leads, try changing them. The ultimate test is to turn off the system right after the post screen disappears. If you can do this, then your power switch is positioned correctly.
Thanks for the idea. I haven't changed anything in the case recently, but I tried disconnecting and reconnecting the power switch lead anyway. No change. The power button does work; it just doesn't POST or boot the first time after a shutdown.
Perhaps it is the power supply. It's about 2 years old. Seems to work fine otherwise but I know they can just go sometimes. Is there anything else I can try to confirm whether it's related to the PSU (short of swapping it with another, which I don't have)?
This sort of problem often occurs when you are over clocking the RAM or CPU, check in your BIOS that all of the timings are at default. I have also had this problem due to a bug in the BIOS check for BIOS updates.
I'm not overclocking anything and my BIOS is up to date.
So here is an update. I ordered a new Corsair TX650W power supply. Supposedly very high quality and 80-plus efficiency. I installed in along with a new quiet case fan. For the first couple of hours, I was getting loud coil whine (super high pitched, constant noise similar to a CRT whine) which was coming from the power supply (not the video card). I was getting ready to RMA it but the problem has gone away, or at least I don't notice the ear-splitting noise anymore, even with my ear pressed up to the PSU. So that is unsettling.
Worse, my power-on problem persists! After installing the new PSU the computer seemed to power-on normally, but now, two days later, I'm getting the exact same issue I got before, only now it sometimes take 3-4 tries to get the computer to POST.
Last night I got a BSOD while working, and the computer automatically rebooted. This is the FIRST blue screen I've seen since installing Win7 RC (and now running retail Win7) six months ago. Now I'm really worried--before Windows seemed completely stable and the only symptom was the power-on problem.
Could this be my mobo? It's a couple of years old but it's one of Gigabyte's "Ultra Durable 2" mobos with all-solid-state capacitors and supposedly very high quality components throughout. I suppose if the old PSU really was bad it could have messed something up, but I have no positive evidence of that since things haven't changed much since I put in the new PSU. Any ideas for what to check/do next?
Problem solved! Turns out it was the RAM! Apparently I have been running the RAM (Crucial Ballistix 2x1GB PC-8500) at 1.8v for 2 years, when spec is 2.2v. The Gigabyte BIOS set to AUTO voltage does 1.8, which seems silly to me given all the different RAM voltage specs out there. The problems started after I began using sleep mode frequently. In sleep mode the RAM is kept powered up so I have to assume that somehow precipitated the problem.
I also removed the DIMMs, rubbed a pencil eraser along the contacts (read somewhere that this can help if the problem is static) then reseated them. I believe this alone did not help the problem, but adjusting the voltage and timings did. Computer is POSTing every time now. Thanks to everyone for the ideas and I hope this thread helps others!
It seems the most likely causes of POST/power on/off problems are a bad power supply, a bad motherboard or video card, and RAM.