System won't boot for several hours

This one has me stumped.

I have a Compaq Presario SR1750NX, from 2005. ASUS ABAE-LE motherboard, AMD Athlon 64 processor, ATI Radeon Xpress onboard video, memory upgraded to 3G, disk upgraded to 1.5TB + 500G. It's been running fine for several months.

I have had at least 3, maybe 4 occasions in the last few months where, when power had been completely removed from the system (i.e., unplugged, not just shut down), the system would not boot when it was powered back up. The lights would come, the fans would spin up, but other than that that, there was no sign of life. There was absolutely no video, not even the Compaq pre-boot splash screen and menu. There were no beeps (although I don't think it has a built in speaker, so that's not terribly surprising). And it would not power down when holding the power switch depressed for more than 5 seconds.

On each occasion, after power had been re-applied for several hours, it would suddenly boot up and run fine.

I just installed the release (RTM) version of Win7, and, lo and behold, it did it again. Except that this time, it wasn't completely unplugged, just shut down for about 12 hours, and this time it didn't come back up, even with power on for 24 hours. (And since it's not even getting to the pre-boot menu, I doubt very much that it has anything to do with Win7, especially since it had been running the RC ever since it came out.)

I theorized that, since the machine is 4+ years old, perhaps the Lithium battery powering the CMOS clock and RAM chip was getting old or something. So I replaced it. And, sure enough, after a couple hours, it came back up.

Except that, after being up for several hours, it went into sleep mode (black screen), and it refused to come out of it. So I ended up shutting it off, and it hasn't come back up since, again, even with power on for 24 hours.

I found the jumper on the MoBo to clear the CMOS RAM, and I did that, but that hasn't made it come back up.

Any suggestions, or am I SOL? I can't think of anything else to try. Any help is appreciated. My finances are really not in shape to build a new system right now!

Dave

 

It might be the power supply going bad. I'm not an expert though. It seems like the 12 V is working for the lights and fans but maybe the lower voltage section has a failed capacitor.

 

Thanks for the reply, GoodTexan, but I don't think that's it. One detail I omitted was that, the first time it happened, I replaced the supply with a high quality (Antec), high power (500W - old one was 350W) supply, and that was just 4 or 5 months ago. Technically, it's possible that the new one has also gone bad, but I don't think it's likely, especially since I initially had the same symptoms before and after I replaced the supply.

 

I agree, Dave. It doesn't sound like the PSU. Sounds more like a bunch of capacitors on your motherboard have gone bad. Take a peek at your motherboard and look for any bulging or possibly even leaking caps and see what you find.

 

I had a motherboard go out in one of my comps a while back. The comp would turn on and all peripheral lights, fans, accessories, etc. would come on with it, but it would never load anything or even begin to boot, as you described. I never left the power on it for very long to see if it would eventually boot or not. Something to consider before thinking about a whole new rig: a mobo that will support the other hardware you have listed is not going to be very expensive at all, I would say easily under $100US just off the top of my head, and would get you up and running until you have the finances to build a new one.

 

Hey that's good to know.. I did think it sounded like a capacitor problem. I also bought an Antec Earthwatts 500W PS. Its much better than OEM.

 

Related question: Is there any BIOS/CMOS setting that would inhibit the boot for some period of time after power on, or until some clock time?

I came home from work last night, and the computer had booted. (The front panel power light was flashing, indicating it was in sleep mode. It would not respond to keyboard or mouse to wake it, but touching the power switch brought the video up, and it was in Windows.) But I'm thinking about CMOS settings, so I tried to reboot and get to BIOS set up. Guess what? Shuts down, but even when powering back on immediately, it wouldn't come back up.

I know there's usually a BIOS setting to turn the computer on at a certain time. (At least there used to be - this is an ASUS ABAE-LE motherboard, if it makes a difference.) If that is set, does it INHIBIT boot until that time?

Also, is there a utility available to at least access, if not modify the CMOS settings from within Windows? (since I can't get the system to boot on command, I can't go into BIOS setup as normally.)

 

That's is some bizzare stuff you got goin on there. In 25yrs of working on pc's I've never seen any kind of bios setting that delays startup. I've seen all the little settings that speed up the boot process, such as turning off the splash screen and bypassing the post screen but nothing like that.

As far as power down settings in the bios, windows takes control over all that when it's running.

I would have to say that your motherboard is totally flaking out on you and most likely needs to be replaced.